NEW ZEALAND AVALANCHE DISPATCH
JUNE 2020
NEW ZEALAND'S AVALANCHE SAFETY JOURNAL
A Seasonal Approach Anna Keeling
Gammack Range Accident Dave Lundin
Trev Streat Interview
Milford Road LiDAR Simon Morris
Proud Partner of The New Zealand Mountain Safety Council
CONTRIBUTORS We'd like to say a big Thank You! to everyone that contributed to our first issue - many of them behind the scenes. We need everyone's contributions to keep this community conversation going strong. Please send us any thoughts, stories, photos, questions, observations, rants etc. We want to read it and we want to keep providing a space for others to read it too! Peter Bilous manages the professional avalanche training programmes for Otago Polytechnic, soon to be engulfed into the NZIT as part of the vocational education reform in NZ. He is also an NZMGA Ski Guide and guided and/or forecasted on most of the continents on Earth. COVID-19 is making him rethink his planetary choice. Peter is also the Convener of the New Zealand Snow and Avalanche Committee (NZSAC) and a regular contributor at the NZMSC Snow and Alpine Conference (SHAC). Ben Corcoran is the Industry Development Advisor-Outdoors at Skills Active Aotearoa. He is a NZMGA Ski Guide and a professional member of the Canadian Avalanche Association.
Jeff Deems. Emerging from the legendary ski town of San Diego, Jeff’s skiing habit was solidified as a student at CU Boulder and through time in Colorado mountain towns. Degrees from Montana State and Colorado State added some small measure of legitimacy to that pursuit. As a researcher at the National Snow and Ice Data Center at CU Boulder, and a co-founder of the Airborne Snow Observatory, Jeff studies spatial variability in snow properties with field measurements, models, and remote sensing.
David Hill (dfh@oregonstate.edu) is a professor at Oregon State University and a National Geographic Explorer. For over 25 years, he has studied how water behaves as it travels from mountain headwaters to coastal environments. He currently co-leads the Community Snow Observations project, one of six citizen science projects funded by NASA to improve the understanding of our physical environment. Hill has recently (2017; 2019) been an Erskine Fellow at the University of Canterbury, New Zealand. No matter the hemisphere, if it is spring time, You’ll find him out surveying the snow between mountain summit and trailhead. Jake Hutchinson is a Lead Instructor for the American Avalanche Institute, technical consultant & instructor for the Mountain Mobility Group, and Membership Trustee for the American Avalanche Association. Currently he spends most of his time appreciating life through the lens of a 15-month-old Malinois.
Anna Keeling is an IFMGA guide based at Castle Hill Village and Salt Lake City, Utah. She runs her own guiding business, trains guides for the NZMGA and AMGA and is a mum who skis a lot and doesn’t get to climb enough.
Gary Kuehn was, until recently, a global snow nomad working as a ski guide, forecaster and educator, now he is isolating in Alaska where snow can be found year-round.
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CONTRIBUTORS Ryan Leong has spent most of his career working on ski patrol at Whakapapa Ski Area on Mt Ruapehu where he runs the snow safety program. Ryan has also intermittently been the MSC forecaster for the Tongariro Region. Alongside skiing, Ryan also enjoys climbing, mountain biking, surfing and parenting- all at a very mediocre level.
Dave Lundin is a ski guide (NZMGA) and avalanche educator. His background is in ski patrol amongst other outdoor work over the last 20 years. Dave is 38 years old, and lives in Luggate with his partner, 3-year-old son and dog.
Mike Lundin has been working in the ski industry all over the world and New Zealand since 2005. Mike has worked as the Assistant Snow Safety Officer at Whakapapa, and spent a couple summers working for the Kiwis at Scott Base. He is now the Ski Patrol Manager at Cardrona Alpine Resort jumping between helping run a ski resort in the winter and a bike park in the summer.
Mike Lynds is based in Wanaka where he runs the snow safety programme at Cardrona (contrary to popular belief we do get avalanches there). He also helps to teach avalanche courses with the Otago Polytech when he can.
Bob Miller is a frequent adventurer who loves all seasons as they offer different thrills for his ski touring, mountain biking, trail running, pack rafting, canyoning, mountaineering and rock climbing missions. To fund these he works in business strategy and accounting consulting.
Simon Morris (simon.morris@downer.co.nz) is a full-time avalanche technician for the Milford Road with over 30 years in the snow industry in Canterbury and Southland. He has a keen interest in avalanche research with his main research focus in 3-D mapping of seasonal snow and the remote collection of snow and meteorological data.
Todd Redpath (todd.redpath@otago.ac.nz) is a PhD candidate at the University of Otago where he also works as a Teaching fellow in the Schools of Surveying and Geography and is involved in the establishment of the Mountain Research Centre. His PhD thesis is focused on the use of remote sensing technologies and spatial analysis to characterise and understand variability in seasonal snow in the mountains of Otago. As a keen snowboarder and splitboarder, Todd is interested in snow as both a water and recreation resource. Jack Saunders works as an Avalanche Technician at Big Sky Resort in the U.S. and has been on the ski patrol in Big Sky for the past 14 years. He patrolled at Porters ski area for three consecutive winters starting in 2016. Jack is usually outside and in the mountains, both for work and play. When not on the snow you’ll likely find him riding his bike in the mountains near his home of Bozeman, Montana. NZAD 03
Editorial
JUNE 2020 On The Cover: Heath Richmond (skiing) and Ewan Mackie making a hefty rain crust look good on Mt Barff. Mt Aspiring National Park, NZ. Image by Mike Lynds.
Kia Ora, Welcome to the June 2020 issue of the NZ Avalanche Dispatch! We've reached out to a lot of great people for our first issue and a lot of great people have reached out to us:
TEAM Managing Editor Brad Carpenter
We begin with our 'Regulars' section and a brilliant photo essay by Mike Lynds to get you stoked for winter. Next up, Tom Harris updates us on the latest happenings at the Mountain Safety Council and Mike Lundin gives us an update on the Ski Area Association of New Zealand.
Assistant Editor
Anna Keeling eloquently leads off our 'Community' section with her piece on the importance of timing during the winter season. Then it's Dave Lundin's must read retrospective of an avalanche accident he was involved in last season. Ryan Leong provides some great insights into the Conceptual Model of Avalanche Hazard. Gary Kuehn presents his thoughts on moderate avalanche danger ratings during the 2019-2020 North American winter, and we finish this section with an interview of the heli-skiing legend Trev Streat.
Holt Hancock
Jake Hutchinson leads off our 'Preparation' section with a piece about experience and situational awareness. We visit with multiple avalanche safety professionals about how they prepare for the NZ winter. Finally, Jack Saunders remembers the professional challenges of a nasty persistent weak layer in the Craigieburn Range in 2017. Francis Charlesworth leads the 'Training and Education' section with an update from the New Zealand Alpine Club on a great new educational initiative they are introducing this season. Ben Corcoran updates us on technical education reform in New Zealand while Peter Bilous outlines the Otago Polytech Avalanche Risk Management Level 5 and 6 programs. We round it all out with a mentorship project being developed by Canterbury local Bob Miller. Our 'Science and Technology' section starts with Simon Morris and the Milford Road LiDAR project. David Hill and Todd Redpath tell us about a NASA funded snowpack observations initiative and Jeff Deems takes us home with his piece about interpreting mapping applications. We think this issue has something for everyone and hope that it will get your winter brain warmed up. It is going to be a challenging season for a lot of operations this winter. Please support our advertisers, ski and ride your local ski areas and take care out there. See you in September with issue two! - BC
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Caitlin Hall
Science Editor With Support From Lynne Wolfe and The Avalanche Review Alexandra Poetschka Inga Booiman Alex Cooper and the Canadian Avalanche Journal
CONTACT Editor or to Contribute nzavydispatch@gmail.com
Proudly partnered with The New Zealand Mountain Safety Council
The New Zealand Avalanche Dispatch is published twice a winter season in New Zealand. No part of this publication may be reproduced without prior permission from the publisher. Opinions expressed in this publication are not necessarily those of the publisher or the editor. Every effort is made to ensure the accuracy of information in this publication, however the publisher assumes no responsibility for errors, omissions or consequences in reliance on this publication.
Contents
22
26
REGULARS
07
Photo Essay
12
MSC Update
16
NZAA Forecaster
17
SAANZ Update
Mike Lynds
Tom Harris
Matt Wilkinson
Mike Lundin
COMMUNITY
35
20
Seasonal Approach
22
Accident Summary
26
CMAH Tutorial
30
Moderate Musings
35
Interview
Anna Keeling
Dave Lundin
Ryan Leong
Gary Kuehn
Trev Streat
PREPARATIONS
43
Left of Woomph Jake Hutchinson
48 Pro Perspectives Multiple Professionals
52
52 One to Remember Jack Saunders
EDUCATION
58
NZAC Training Francis Charlesworth
60 Education Changes Ben Corcoran
61
61
Otago Polytech
64
Slow Skinners
Peter Bilious
Bob Miller
SCIENCE and TECH
67
67
Milford Road Lidar
70
Community Obs
74
Map Tools
Simon Morris
Dave Hill
Jeff Deems
Photo Essay Featuring: Mike Lynds
Taken on one of those rare days when perfect stellars were falling straight from the sky. Probably unsurprisingly, this wasn’t taken in NZ - it was during a season in the French Alps.
Mike Lynds NZAD 07
Mike Lynds NZAD 08
Heath Richmond, scoping lines somewhere near Ben Nevis in the Hector Mountains. We had a fun scramble along the ridge through this little tunnel in the rocks, which made for some cool framing.
Ewan Mackie takes a moment to take in the view after a rather dicey descent off Cascade Saddle. Four hot days with no freeze and a totally rotten snowpack made for terrible skiing and perfect glide slab conditions.
Mike Lynds NZAD 09
Mike Lynds NZAD 10
Rain runnels always make for interesting photos! This was from an attempt on Mt Barff in the Matukituki; we got turned around by a questionable snowpack where the rain crust started to turn to fresh snow. It was a good test of the ski edges skiing back down these runnels.
So hard to stay angry at these guys even when they tear everything you own to shreds. A young Kea checking to see if my skis are edible on Cascade Saddle.
Mike Lynds NZAD 11
Mountain Safety Council Early Winter Updates By Tom Harris Partnerships Advisor Alpine NZMSC We here at the MSC are excited and proud to be a part of the New Zealand Avalanche Dispatch! We look forward to providing content in the coming issues in the form of sharing all the developments that we are working on in the avalanche space amongst other interesting material. We hope you find it informative and a good read! This is surely the beginning of an unusual and challenging year for our space, so now more than ever, we're wishing you all a safe and enjoyable winter, and hopefully some excellent days in the snow. InfoEx Improvements At the time of writing, MSC is completing an array of improvements to avalanche.net.nz. These include new features and updates to the Public Observation tool, and most expansively, within the subscriber only section called InfoEx. Fortunately, this work is not affected by the onset of COVID-19 restrictions and is moving forward as planned. MSC would like to thank everyone who gave feedback on these products in the interest of improving their efficiency, functionality and the sharing of information for the benefit of public safety. Software and IT development is expensive, so updates are always prioritised based on needs and wants. We do believe we will be able to make some significant improvements during this off-season, particularly to InfoEx. This should make contributing information easier and less time-consuming. These improvements will cater to the avalanche hazard management software requirements of our subscribers, while also encouraging more data collection from all users, public and professional. Below are some examples of the features to be added/improved: Some auto-reloading data in the Hazard Analysis (InfoEx feature). Updates to presentation of completed Hazard Analyses (InfoEx feature). Update of terminology and adjustability of certain parameters in the Hazard Analysis (InfoEx feature).
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Mobile phone user experience improvements across NZAA: public observation tool and InfoEx location data assigned to all observation types (avalanche, snowpack and weather obs.) (InfoEx feature). Enhanced forecasting features such as a draft and publish later function. Improved Facebook sharing function for public observations linking public observations to forecast regions, and easier filtering of this info for InfoEx subscribers. Extending time public observations pins shown on map and creating a searchable archive of all public observations from the season in InfoEx. Addition of a Backcountry Access Policies page to NZAA website. Please get in touch if your ski field has a policy to provide for this! We will provide further updates on what work was completed in the next issue of NZAD. For enquiries or to discuss further please contact Tom Harris at tom.harris@mountainsafety.org.nz Public Observations 2020 Many of those reading this will already be familiar with the Public Observation tool on the NZ Avalanche Advisory (NZAA) website (Figure 1). The tool was added to the NZAA back in 2018 in an effort to help fill the snowpack/ava-
Figure 1: Screen shot showing the NZAA public observations page.
lanche data void in the more remote forecasting regions here in NZ. Like the MIN (Mountain Information Network) observations used by Avalanche Canada, these observations are a great way to create a community of public data-sharing, so people have a better idea of what is going on in their area in order to make more informed decisions on planned trips. The NZAA Public Observation tool is still in its infancy. However, we are seeing increased uptake, with the 2019 season seeing 3x more snowpack and avalanche observations than the previous season. MSC has a three-pronged strategy to increase uptake again in 2020. This is composed of: Improvements to the user experience of the Public Observations tool; particularly on devices. We will also allow for more photos to be added to observations. The return of our Public Observation competition for the season The added ability to effectively share submitted Public Observations directly to Facebook groups or your own timeline. I’d like to particularly expand on that final point. I’m sure many of us reading are members of at least one backcountry snow-sports group on Facebook. Some notable ones like Nelson Area Backcountry Snow Sports, Canterbury Ski Touring, and many others have large group sizes and very active members. One of the most valuable components of these online communities is the sharing of conditions and observations of the snowpack and other route components around the applicable region(s). These social posts are a great means of sharing what you’re seeing and experiencing with fellow backcountry users in the form of photos and descriptions. The one problem with this style of reporting, however, is that the excellent observational data is spread between a number of pages (of which many are private) and it is not particularly efficient to sift through if looking to get a broader picture on current conditions. MSC believe we have a solution to this, which would help merge a lot of this data into a single location (NZAA) while also continuing the excellent dialogue and communityfocused nature of these backcountry Facebook pages. MSC is creating the option to share your Public Observation to Facebook as you submit the observation on the NZAA website. It would be a very simple and streamlined process, with the ability to share to specific groups such as these backcountry snow-sport pages. There would also be the ability to add a caption and viewers of the post would have the option to click-through to the full observation on the
NZAA site. Our thinking is that many people are already making observations on Facebook but not on the NZAA simply due to work duplication. By allowing submitters to share to Facebook at the same time, we hope to capture more of these observations in the NZAA. There are three key reasons that observations in the NZAA forum have added value. 1) They are all located in one centralised place where it is easier to oversee a multitude of observations relatively efficiently in planning for a trip. We can also pinpoint near-exact locations of observations on a map and provide great detail. 2) The observations are stored and organised to assist forecasters and other snow safety workers in each region. This results in more accurate and informed forecasts for the public. 3) The data from these observations will build over the years to create a database of observations that can be extremely useful for insights work the MSC does, as well as for academic research into a variety of areas such as snow safety, decision-making and climate change. As readers of this publication, I expect you all take the danger of avalanches very seriously, and hopefully can appreciate what we at MSC are trying to accomplish with this tool. If you see a good observation in your snowsports Facebook group this winter, please kindly remind the person posting about our NZAA Public Observation tool and encourage them to submit so we can continue to improve uptake and data sharing! If you are a group admin perhaps consider a note in the group description on using the tool. Alpine Skills Series Release The MSC in partnership with NZMGA, NZAC and NZOIA have created a five-part video series on some essential alpine snow skills for those new to the discipline (Figure 2). While far from exhaustive, the videos hopefully will serve as a brief introduction to some
Figure 2: Screenshot from the MSC website showing the new Alpine Snow Skills Series page.
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techniques used to travel safely in the snow when participating in winter/spring alpine tramping or pursuing beginner mountaineering trips. Viewers are encouraged to take a full alpine skills course and to be well educated and equipped to deal with alpine environments and the avalanche hazard. While there are many variations on techniques used in this discipline, we have focused on having some clear messaging and making sure everything we demonstrated was correct and safe, rather than “the best way”, as this is clearly subjective. Update: The onset of COVID-19 has delayed some final content recording, so the release of these videos may be delayed to spring 2020. But keep a lookout for them on our social media channels and please share with those who are a bit newer to the scene. They may even serve as useful imagery tools when teaching family and friends. Avalanche Incident Insights Back at the 2019 Southern Hemisphere Alpine Conference (SHAC) , MSC presented some preliminary insights on avalanche incidents and fatality data. These insights combined data collected from NZ Police, Rescue Coordination Centre NZ, InfoEx platform, NZ Coronial Services and ACC. This data has given us some great initial findings, particularly around what types of avalanche incidents people in New Zealand are getting involved in. One of the key Insights from the presentation was the fact that the vast majority of Avalanche Incidents involving humans occurred when the NZ Avalanche Advisory
was forecasting a Moderate or Considerable avalanche, in the relevant region (Figure 3). There is mixed news here: On the one hand it seems as though backcountry users do take seriously the times when avalanche danger is High and Extreme, as incidents are very low. However, 56% of incidents are happening when the forecast is Low or Moderate. It’s hard to conclusively say why this is, but it may stem from a combination of factors: the participation being higher at these times, people underestimating the fact that avalanches are still possible at these times, and the possibility that people are not effectively assessing conditions in the field and making the appropriate terrain considerations to manage the avalanche hazard. Regardless, something to keep in mind this upcoming season. When the forecast is Moderate or Low, there is still danger present, and appropriate decision-making and risk management are still required. MSC is doing more work on these Insights and will share results as they become available. One example of this is the collaborative work we have undertaken with the University of Otago’s Mountain Research Centre. Avalanche Incident Data Exploration Collaboration with Otago University After the MSC presentation at SHAC an opportunity arose to collaborate with the University of Otago on further analysis of this data. In conjunction with the Mountain Research Center—a group of researchers from the School of Geography and School of Surveying—we agreed to explore ways in which we could draw out further insights
Figure 3: Avalanche incidents involving humans distributed across the danger rating at time of incident in relevant region. NZAD 14
Figure 4. Spatial visualisation of avalanche incident findings Lake Alta area, Remarkables Mountain Range, Queenstown.
and potentially visualise the data in an effective way. This work is still ongoing but over the summer a student-led project kicked off the initial collaboration and has resulted in the first map-based 3D spatial visualisation of the avalanche incident data (Figure 4). These spatial layers, while still in development, have the potential to provide snow safety experts with insight into the terrain characteristics (e.g. slope angle, aspect, elevation) with the greatest frequency of human-triggered avalanches. While this does not provide a direct insight into ’dangerous terrain’, it is useful for analysing areas where decision-making by backcountry users was not in line with the conditions and where people are being ‘caught out’. An example of the spatial visualisation of the avalanche incident findings (see Image 3) is the proportion of avalanche incidents reported in five elevation bands (Below 1,500m; 1,500 – 1,750m; 1,750m – 2,000m; 2,000m – 2,250m; Above 2,250m) for the Queenstown Region. Lake Alta in the Remarkables is visible in the centre of the scene. You can explore the data yourself by visiting this webGIS: https://arcg.is/0vzCC Remember, this data is for visual demonstration purposes only as it is still in development. This should not be used as a risk management tool at this time. The collaboration with the Mountain Research Centre at the University of Otago continues to grow, so stay tuned for additional data exploration and findings.
Tom Harris MSC Partnerships Advisor-Alpine
Tom Harris (tom.harris@mountainsafety.org.nz) has worked in the outdoor sector for nine years. Between 2012-2018 he guided on both the Fox and Tasman Glaciers and has been a member of the New Zealand Mountain Guides Association (NZMGA) since 2014. While guiding he completed a Bachelor of Science degree in Geography and Economics from the University of Otago. Prior to starting with the MSC, Tom acted as the Winter Search and Rescue Lead and Field Safety Coordinator for the United States Antarctic Program (USAP) at McMurdo Station, Antarctica. When he's not riding his bike, surfing, or learning to fly in Wellington, he is usually tramping, skiing or occasionally climbing all over New Zealand and overseas.
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FEATURED FORECASTER
Matt Wilkinson NZAA Forecaster, Nelson Lakes Region
Interview By Tom Harris
MSC: How did you get into avalanche forecasting?/What’s your avalanche/snow safety background? I started work at the Remarkables in 1987 at the age of 19, having lived in Mount Cook Village and climbed for 3 years. My career as a professional Patroller would span 21 years and was my winter occupation while I worked as a mountain guide during the summers for the same period. After completing a BHSc in Paramedicine, I shifted to Nelson and have been working in ambulances and helicopters as an Intensive Care Paramedic. For the last 12 years I have been the NZAA Avalanche Forecaster for the Nelson Lakes Forecasting Area. This has been a fantastic opportunity to continue to be an avalanche forecaster and to liaise with the Patrol team at Rainbow and the Staff at DOC. So given the fact I am now an old fella I have been involved directly with an Avalanche Program for 32 or so years. Dinosaur! MSC: What other work are you involved in within your region for the season besides forecasting? So my main work these days is working in the Nelson Marlborough Rescue Helicopter as an Intensive Care Paramedic. This allows me to see the park often from the air. I am also doing some avalanche awareness courses for an increasingly enthusiastic group of backcountry tourers in the Nelson Marlborough Region. I have also been fortunate to guide 5 ski touring trips to the Antarctic Peninsula in spring. Best things about winter recreation in your region? We are blessed with some excellent and reasonably easy to access backcountry that contains both really good touring and mountains of decent quality. There are a number of great huts within these areas as well. Most overlooked avalanche safety points in your region or in general that you typically see or hear about? Nelson/Marlborough doesn't have the same sort of alpine culture that places like Methven, Wanaka, or Queenstown have. As a consequence the role models, training courses, and equipment are less available, accessible, and obvious to find. So the main messaging here is still about training with and using avalanche safety equipment and the difference between snow inside and outside the ski area boundary. What are the unique challenges for forecasting in your region? Probably the lack of operators to provide information to the InfoEx (Industry data-sharing platform for snow observations). Getting real time data on natural avalanche activity can be a challenge at times during storms. As a consequence we have created a facebook page Nelson Lakes Winter Backcountry Users with 450 or so members that helps with communication about current conditions among group members. If there was one unique takeaway winter backcountry users should know about your region what would it would be? We often start with shallow and brittle snow at the start of the season that has consistently created persistent weaknesses for large parts of the early winter season. We also tend to have a long spring season that can generate large, wet snow avalanches right down to the valley floors where tramping tracks exist, some serving the increasingly popular Te Araroa trail. Any personal winter objectives in 2020? Hopefully make up for recreation lost to lock down!! Ski!! Ski off some hills. I also want to continue with the avalanche awareness training that we have made a good start on in the last few winters. Hope to see you all out there. NZAD 16
The Ski Area Association of NZ By Mike Lundin If you are one of the thousands who look forward to strapping some planks or a board to your feet in the winter months and heading to your local ski resort, you have already formed a relationship with an organisation called SAANZ - even if you have no idea what that is. The Ski Area Association of New Zealand (SAANZ) provides a platform for ski areas to communicate and establish industry best practice across all aspects of ski resort management. It is not compulsory for ski areas in New Zealand to be members of the Association, but there are only a handful that haven’t signed up. My name is Mike Lundin, I’m the Patrol Manager at Cardrona Alpine Resort and the SAANZ Patrol representative for the commercial ski areas in the South Island. I sit in on two subsidiary groups flying this flag (the Avalanche Education Working Group and the Snow and Avalanche Committee), and I co-ordinate the Patrol HODs group which feeds ideas back into those groups. Through my involvement with these groups I have realised what an important part of winter SAANZ is for all of us. I began writing this piece before COVID-19 had arrived in our small island nation to turn life, business and society on its head. The SAANZ Executive Committee has already come together to discuss the options available to the ski industry in NZ - the Executive Committee includes the CEOs and GMs from NZSki, Cardrona, RAL, Mt Dobson, Snowplanet and Winter Games NZ. Only time will tell what the long-term implications are for us all, but we can expect that this winter is going to look very different to seasons gone before.
Figure 1. The New Zealand Skier Responsibility Code developed by SAANZ.
SAANZ projects include things like updating the Snow Code. iThis is messaging and signage designed to help keep all snow users safe and to promote positive interactions between everyone on the hill. Another recent project was revision of the NZ Explosives SOP. This document spent some time in limbo, but thanks to the efforts of a number of individuals from various ski areas, and outside agencies such as the Milford Road Alliance, we are now all working under the same umbrella and guidelines when using explosives. The strength of the group comes from all members working towards a common goal, wanting to improve systems and processes across the industry. SAANZ is not a regulatory body and therefore cannot require particular action from anyone; WorkSafe is the organisation to investigate incidents and require changes to systems and policy should a significant event occur. However, collective action through SAANZ enables the ski industry to create best practice guidelines as industry experts. Ski areas pay to maintain SAANZ membership, and the price differs depending on the size of the ski area. This system removes a barrier to smaller club fields being involved. The idea is that everyone can access and contribute to resources and documentation, as SOPs are updated and new ideas are formed within the group. A current project of the SAANZ HSE group is developing a digital platform for the National Incident Database (NID). You may have contributed to this database after hobbling into a ski area medical centre and filling out a form to describe your injury… For many years the New Zealand Mountain Safety Council (MSC) supported the back end of this system, enabling ski areas to look at the data and implement changes in hazard management if trends were found in guest or staff injuries. SAANZ is taking over this role, and digitisation of the database will bring efficiencies both in data collection and analysis. All going to plan, it’ll be up and running for the 2020 winter season. In order to have recommendations changed or procedures updated, there needs to be industry-wide discussion and agreement. International best practice informs a lot of this, but some things require a uniquely NZ perspective and solution. In 2019 the Patrol HODs group updated the SOPs around working with explosives in the ski industry. The final push was coordinated by Andy Hoyle (SAANZ Rep for the North Island/bit of a legend in the ski industry) and myself after talking to the various HODs around the country NZAD 17
and getting SAANZ HSE committee sign off. As you can imagine, there were many robust discussions around a few of the finer points which affect ski area operations in different ways. The wider SAANZ group meet twice annually. Ski areas take turns to host the conference, show off their latest upgrades and talk through the challenges of operating in different parts of the country. I am slowly learning, and maybe you are too, that while linking a few turns on a groomer may seem straightforward, in reality it is anything but. As with any industry, there is a huge amount of unseen work that goes into making it happen. Clear communication between the various moving parts is key to us all travelling in the same direction, and SAANZ ensures this can happen across the ski industry in NZ. Stay well, and look after each other this winter.
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COMMUNITY
20 Anna Keeling - A Seasonal Approach 22 Dave Lundin - Accident Summary 26 Ryan Leong - Considering the CMAH 30 Gary Kuehn - Scary Moderate 35 Trev Streat - Interview
A Seasonal Approach to Terrain By: Anna Keeling Late December in Utah, a couple of years ago I was in a second hand gear shop. A guy asked me what I thought about conditions on the Salt Lake Twins. At 3450m in altitude, the Twins soar 2000 metres above Salt Lake City and there’s a fair amount of terrain to get through to even top out on their windy and lofty summits. People often ask me what I think about conditions. I think about conditions most of the time. I watch the mountains from the valley - whether I am in Castle Hill Village or in Salt Lake City. I’ll look out the window before I consult any website (even when it’s dark). I’ll look for wind plumes, for frost, for fresh snow, for rain, for snow melting off the roof, for clear skies - and every day I wonder “what has changed?” “Why would you go up Twin Peaks tomorrow?” I asked the guy in the shop. “I have the day off and want to do something big,” he replied. We chatted about conditions. About the persistent weak layer that was currently haunting the Wasatch snowpack, the basal facets that were still less than a metre down in the pack. The wind plumes that frequently pour off the highest summits of the Wasatch, the 5000+ foot/1500m approach to these summits and the sheer volume of complex terrain to be travelled to even get a view to the tops. My friend Nancy grew up in Jackson Hole. Now in her early 50’s, she told me that when she was at high school, no-one would ski Glory Bowl until mid April. Glory bowl is the fantastic toilet-shaped bowl that rears over the village of Wilson and the Teton pass road. In Nancy’s high school era, common thinking was to let the pack become deep and settled before hitting Glory bowl. Now days it’s skied all season from woe to go. People get caught there. Sometimes the whole thing goes big and flushes out onto the highway. Froth. Films. Social media. Big talk. It’s well and truly alive in the US but we are not far behind. Great snow is a scarce resource (unless you are one of the fortunates who have so many back-to-back seasons that you’ll happily sit out a powder day to avoid crowds and avoid having to witness people doing scary things). The hit list is long, time feels short. You’ve lined up the weekend and damned if you’ll let poor conditions stand in your way.
“Dude,” (sometimes I try to use bro-speak to get my message through), “Why not wait?” I was slightly impatient but trying to be nice: “It’s so early in the season, it’ll be dark by 5. There’s a persistent weak layer less than 3 feet down, it’s cold, there’s wind blowing right now up there. You have no margin for error at this time of year. The pack is not yet settled. There is no reason to go there. Wait. Wait until late February when the snow is deeper, when there have been a few fine days in a row.” After 22 seasons back-to-back and all the countless before that - the seasons I ski patrolled or ski guided in Canada - I must have skied 65 seasons by now and I’m 50 - I’ve learned a couple of things about patience: Choose your objectives according to the time of year. This is my strategy: Every season I try to teach a few avalanche classes early on, before starting to guide. This eases me into the season - it forces me to train with beacons, shovel and probe, it sets up my pack and systems, it gets my head in the snow - looking at layers, familiarising myself with the snowpack from the outset. It also helps me set up a base fitness for the rest of the season.
Another trick I have in North America is to eke out my summer in NZ and try to arrive late so that I miss the basal facet/persistent weak layer/early season excitement. This isn’t always possible but if I can get away with arriving in mid to late January, I’ll do it. This means extra caution - my head has not been in the pack so I must move carefully. I’ll try to line up my first few tours with a local forecaster, guide or experienced friend. It doesn’t work the other way around but luckily we don’t see persistently weak layers in NZ as often. Wherever I am, I have the daily avalanche advisory emailed to me from first snow. Even if I’m late to arrive, I have some idea of how the weather and snow pack are developing. Once I’m ensconced into my season, I try to try to estimate each morning what the hazard rating will be - before reading the advisory. This keeps me on my toes, looking, thinking, evaluating. If there is a weak layer in the pack - and the daily avalanche advisory plus some targeted digging will confirm this - I choose simpler terrain. I’ll potter around
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in casual places with low angle slopes, where I can avoid being under other users and meadow skip around on 30 degree slopes or less. At least I’m out. As the season progresses into mid-late August (or February/March) and I become more comfortable with conditions and the pack deepens and settles, I can ease into bigger terrain. I talk with others about what they have seen. My guided trips will go further afield. I may dig less and probe more. When spring arrives in mid September, I’ll venture out into glaciated terrain. Hopefully snow will have filled in crevasses, the days will be longer, it will be warmer.
Hear more from Anna Keeling on the Utah Avalanche Center's Podcast with UAC forecaster Drew Hardesty by clicking here.
I like the guy in the shop in Utah. I want to see him have a fun season but I want to see him in the shop again. I hate it when people I know and like become statistics. He agreed that it was too early for the Salt Lake Twins. He hadn’t thought about that aspect of seasonal planning - that waiting until spring will be more fun, less scary, less cold, less dark. It will make more sense. The peaks should still be there next year if conditions never come right this time around. In the meantime, I’ll try to find good snow, interesting tours and terrain and keep my rigmarole of seasonairing on the move.
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Close Call in the Gammack Range By Dave Lundin Last year on August 13th at 3:15pm I triggered and was caught in a small and shallow avalanche (size 1.5) while guiding a group of four experienced, fit and capable skitouring clients. We were skinning/traversing on a southerly aspect at 1600m in Tin Hut Stream in the Gammack Range, Mt Cook National Park (Map 1). I sustained a dislocated and broken shoulder and many bumps and bruises due to my violent ride through shallow rocky terrain. I also smashed my transceiver which was in my leg pocket. Luckily I was not buried. At this stage I’m seven months post-accident, and my rehab programme consists of one, hour-long physio session once a week. I go to the gym every other day for a couple of hours along with having exercises/stretches three times a day (everyday). I haven’t worked since August, progress is positive despite being frustratingly slow.
The surface condition of the slope that released was “variable” - some members of the group had ski crampons on, and in places I would describe the snowpack as below threshold. There was a 10m gap between me and the next person on the skin track. I came across a small gully-feature that would not have been visible if there had been another 20cm of snow on the ground. There was no visual difference between the surface condition of this feature and what we had been skinning across for the previous 45 minutes. Once I stepped into the gully (5-6m wide, 100-150m long) the slope whumpfed… For what seemed like a couple of seconds nothing happened and I thought that I had got away, unfortunately that was not the case. The slope cracked above me and accelerated. In this moment I decided to try and run across the moving blocks to get to the far side of the
There is a lot of research around group management, snow structure, avalanche rescue, mindset, forecasting, likelihood, consequence and so on… I’m not going to cover any of this, I want to give you a frank personal account of my experience. My hope is that after sharing my experience you will think about your own decision-making and risk assessments when travelling in avalanche terrain. We were on our second day of a multiday ski-touring trip. We had flown in on the tail end of a three-day weather window. Recent storm snow was bonded really well and we were operating under an ‘open season’ mindset. During the first night the forecast of increasing wind and high cloud came into effect. This changed the game in terms of snow quality and stability. My mindset changed to ‘assessment mode’. We spent the first few hours of the day skiing lowangle slopes close to home (Falcon’s Nest Hut) and had pulled back on a slope at 1800m (easterly aspect) that was producing propagating test results, ECTP 16 down 24cm (multiple hand shear’s across southerly half aspects 15001800) . We retreated to the hut for lunch and a brew, and during this time another touring party stopped in to say hi and talk conditions. They had managed to find some shelter from the wind lower in the valley and after a discussion we decided to go and have a look for ourselves (the time was around 2pm). NZAD 22
Map 1. Showing the location of the accident in the Gammack Range near Aoraki/ Mt Cook National Parkl
gully (bear in mind, we were in touring mode). I made it to the far side and was standing on rocks out of the moving avalanche when some debris washed up out of the gully and hit the tail of one of my skis, spinning me around back into the avalanche. It was a violent ride (about 200m) with the run-out littered with rocks. I was lucky that I ended up on the surface of the avalanche once it stopped (I’ll get back to this point later). When the avalanche stopped I was able to sit up and wave to let the group know I was “ok”. The first of my clients arrived after a few minutes and we decided very quickly to activate the PLB (personal locator beacon), and to try get a call out on the satellite phone. I was unable to walk due to multiple impacts during the event. My left shoulder was dislocated, and I found out later I had also broken three bones in the same shoulder. In the time it took to get a call out RCC (the Rescue Coordination Centre) had already picked up the beacon activation and were organising resources. I’d ended up on a slope of about 35 degrees so it was decided that I should be moved about 100m to a flat area for a helicopter pickup. I always carry a rescue tarp and this was used to drag me down the slope. This was not pleasant as I was in a world of pain. An hour and a half after the beacon activation, the Mt Cook Search and Rescue team landed on site. I was flown to Mt Cook, transferred to the waiting Westpac Rescue Helicopter and taken to Christchurch Hospital. The rest of the group were evacuated in a second helicopter to Mt Cook. I spent 10 days in hospital, was in surgery for seven hours and walked unaided after six days. The rescue phase of this event from my perspective went smoothly. My clients kept clear heads and communicated clearly with each other. Cold management was a high priority along with the group’s wellbeing. Contingency plans were discussed and there was a lot of self-checking going on. As a winter guide I have completed a number of assessments along with ongoing training and professional development. I had not prepared myself to be the one in need of help. In the moments after the avalanche stopped, shock started to set in and a wave of uncertainty and vulnerability swept over me. There are several lessons I learned from this accident: Transceiver: I talked about how I was lucky to end up on the surface and not buried. I was carrying my transceiver in my pocket (zipped up and the transceiver tethered to my belt loop). I have been doing this for a number of years for the ease of accessibility. As a guide and avalanche tutor I tend to use my transceiver a lot (demonstrations, checking clients’ and students’ transceivers and so on). During the
X-rays of the aftermath of the accident: seven hours of surgery, multiple pins and plates, and a long, long convalescence.
avalanche I hit a number of rocks, my transceiver took a big impact and probably saved me from a broken leg. However as a result of this impact, my transceiver stopped working. I can no longer personally justify carrying my beacon in my pocket and will return to using the harness that comes with it. Always check the manual and make your own decision while taking on board the manufacturer’s recommendation when it comes to how you carry your beacon.
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Catastrophic damage caused to the transceiver rendering it in operable. The transceiver was secured inside the author's front pocket at the time of the accident.
Preparation: A former colleague of mine always talked about, “What if?” I can’t rate the importance of carrying enough equipment EVERY time you go out-of-bounds. This may seem like a simple concept to all of you, however have a think about how prepared you really are when skiing the ‘side country’ - do you have enough gear when just dipping your toes into Tarn Basin or a quick line off Gottlieb’s? Think about the avalanche survival graph. You have less than 10 minutes to locate and dig up an avalanche victim for the best possible chance of survival. YOU need to have the skills and equipment to self-rescue. Staying warm is a big deal what are you carrying to keep yourself warm? Do you carry a pad to insulate a patient from the snow? I don’t change the contents of my pack between personal and work trip into the hills. Here is a short list of what I carry: repair kit, first aid kit, communication device(s) (radio, plb, sat-phone… etc), avalanche rescue equipment, spare layers (not just for me!), emergency shelter/rescue sled, food/water…. This is on top of any technical gear required for the specific objective or goal. Heuristic traps: If you’re not familiar with these I suggest you do some reading:
https://arc.lib.montana.edu/snowscience/objects/issw2002-244-251.pdf NZAD 24
Heuristic traps are everyday methods that we use to gather information. We tend to fall back on them when we do not have enough information. It’s likely that you can relate to several of these factors, in everyday life as well as in the mountain environment. It’s about managing risk while being aware of any mental shortcuts. I’m not going to go in the details of the different traps here as this has been welldiscussed by McCammon and others. Reflecting on the heuristics during this accident showed some red flags or ‘lemons’ leading up to the incident: I fell into the scarcity’ trap. Scarcity; this is about making a judgement on the stability of a slope based on other ski tracks or other groups decisions. I hadn’t decided to cross the gully feature because someone else had (we were the only group to cross the slope) but I had decided to head out that afternoon after the conversation with the touring party that had stopped in to say hi. My decision wasn’t solely based on that conversation but I did sway my thinking. This accident has affected me physically in some very obvious ways, although it’s the underlying mental healing that has been a bigger hurdle to overcome. Living in a place like Wanaka there are a lot of people to talk to about traumatic accidents in the mountains. I have an incredible,
widespread support network. I can’t thank my family and friends enough for how they have helped me through the last few months. I continue to have internal battles about my decision-making on the day and the events leading up to the accident. The NZMGA put me in touch with a trauma counsellor who I had a good chat to. These sort of accidents will affect everyone differently. If you have gone through something like this yourself but are yet to talk to someone who is independent from your day-to-day life, I would highly recommend it. Being open and honest with your family and friends about how you are feeling will help you recognise behavioral patterns that might not be normal. Thank you for the opportunity to tell my story. I hope my experience will help others to stay safe. I’m looking forward to getting back to recreating and working in the hills.
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A Look at the Conceptual Model of Avalanche Hazard By Ryan Leong All figures courtesy of Grant Statham. With the Conceptual Model of Avalanche Hazard (CMAH) now becoming the industry standard format for assessing and forecasting avalanche hazard it's a good time to clarify a common misuse of one of the components of it which has a significant effect on the likelihood rating that you get. Bringing this to the attention of the NZ avalanche industry will hopefully lead to a better understanding of the workflow used by the CMAH, and keep all users of it on a level playing field. First, a quick background on the CMAH: If you are not familiar with the CMAH have a read of the current version of it here:
https://link.springer.com/article/10.1007/s11069017-3070-5#Tab3 Everything below will make more sense once you have done this. It was first developed in 2008 by Grant Statham and others and has been revised a few times until its current
version (2017). In a nutshell it “identifies the key components of avalanche hazard and structures them into a systematic, consistent workflow for hazard and risk assessments” as stated on the current version. After setting the context of the operation and temporal / spatial scales It follows 4 key questions: 1. 2. 3. 4.
What type(s) of avalanche problems exist? Where are these problems located in the terrain? How likely is it that an avalanche will occur? How big will the avalanche be?
Figure 1 illustrates this simple, and robust structure. CMAH has widely replaced the old stability rating system used for decades, so these days we hopefully have people talking more about a windslab problem on west aspects above 2000m which has a possible likelihood of triggering size 2’s, rather than saying “stability is fair”. It’s much more descriptive, easier to understand and gives us more. It makes sense.
Figure 1. Structure of an avalanche problem showing the work flow used in the CMAH. NZAD 26
Figure 2. Definitions of spatial distribution ratings.
What have some of us (myself included) been doing wrong?
ignoring or blacking out all other parts of your operational terrain / tenure.
One thing that never quite made sense to me was the difference (or lack of) between the location, and the spatial distribution. If the location for a particular problem was southeast facing aspects 1200-1800m then surely the spatial distribution would be ‘specific’. The definition of specific being:
For example: Your operational setting may be the "Big Boys Basin." Within this area you have identified a windslab avalanche problem on north facing aspects above 1200m. This is your location for the problem. The next step is to consider the spatial distribution on this windslab problem within north facing slopes above 1200m. In this example let’s say it has been blowing with nice light winds which have deposited a uniform windslab across all north facing slopes, it's not only found on steep convex rolls, or upper ridge crest features, it’s nicely layered over everything that faces north. This would mean it is ‘widespread’ - because you have considered its spatial distribution within the stated location.
"The avalanche problem exists in terrain features with common characteristics.” How could it be anything other than that? It is specific to southeast facing slopes at those elevations - it’s not anywhere else. Similarly if you had a bunch of snow with no wind and ended up with a storm snow problem, the ‘location’ would be on all aspects and the ‘spatial distribution’ would be ‘widespread’ - the definition of this is ‘the avalanche problem is found in many locations and terrain features’. This seemed like it was just adding in another step which you didn’t really need to do - maybe it added a little more information but didn’t have any effect on the outcome of the likelihood rating. Numerous discussions with people throughout the industry didn’t clear this up so I read and reread the paper, and kept thinking about it until the penny finally dropped and it all seemed really obvious and made perfect sense. We then adjusted the way we used it in our operation and it immediately seemed far more logical both as a forecaster using it to evaluate avalanche hazard, and as a team member interpreting the information during briefings. I wanted to make sure I wasn’t going full rogue so I went straight to the source and got in touch with Grant Statham. He confirmed that this was how it was intended to be used, and also mentioned that lots of folk had got in touch with him regarding exactly the same issues that we were having when we first adopted it. So it’s a pretty common problem, and the more people I talk to about it both here in New Zealand and North America the more the same issue crops up. How should we be using it? You define your location, and then consider the spatial distribution only within the defined location - essentially
Another example might be a surface hoar layer which is found at all elevations buried on south facing slopes, but is very patchy. There seems to be no pattern to where it is and isn't within those south facing slopes. You can’t find it in many places, but it still pops up from place to place (figure 2). In this case: THE PROBLEM: Persistent slab. THE LOCATION: South facing aspects, all elevations. SPATIAL DISTRIBUTION: Isolated. From these examples you can see how it is perfectly feasible to have a problem which is specific to certain terrain features, which is actually rated as either widespread, specific or isolated. See images one and two on the next page to get a visual example of how this works. So why does this matter? It matters because the spatial distribution that you choose affects the likelihood rating that you get (figure 3). This is very important because likelihood is half of the hazard equation. Likelihood is determined by combining spatial distribution and sensitivity to triggers. Let's say for a given problem that
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Image 1. Suppose the terrain in this photo is the area you are assessing for avalanche hazard. The wind has been blowing from lookers left to right (south to north), transporting snow, and creating new windslab on north facing slopes - which happen to be the bright sunny slopes in the photo. In this case we can define our location for the windslab problem as north facing slopes.
you have a ‘reactive’ sensitivity to triggering. Depending on whether you call the spatial distribution widespread, specific or isolated, you could end up with a likelihood rating of Very Likely, Likely, or Possible. Quite a difference.
Image 2. Now that we have defined our location we can exclude the rest of the terrain in the area and only focus on the north facing slopes which are the unshaded areas in this image. What is the spatial distribution of the windslab within these areas?
are. Defining terrain by aspect and elevation is a common language. However some operations may choose to define location by an operating zone such as a drainage, range, particular path, ski run / route or terrain feature. The nature of the operation will determine what is the best way to define the location. For example let’s say a guided ski touring operator has a tenure of 5 drainages and they have a windslab problem which only exists in the western most drainage. In this case they may choose to define the location of this problem by drainage as opposed to aspect or elevation. Assuming the windslab is only on north aspects it would look something like this: THE PROBLEM: Windslab THE LOCATION: West Drainage SPATIAL DISTRIBUTION: Specific (because the windslab exists on terrain features with common south aspect characteristics within the West Drainage.)
Figure 3. Likelihood of avalanches as a result of combining spatial distribution and sensitivity to triggers.
Then you would carry on with sensitivity to triggering etc.
So if more people across the industry are using the spatial distribution part accurately, then more people will be getting consistent likelihood ratings which is a good thing. What one person or operation calls Possible, another calls Possible, rather than my Likely is equal to your Possible. Apples with apples (see figure 3).
Whereas if you defined the same problem’s location as north aspects, the distribution could be widespread, specific or isolated depending on how that windslab was distributed within north aspects. It’s all about how you choose to define your location.
One important thing to note is that - going back a step - the location does not have to be defined only by aspect and elevation. That has just become the most popular default because that is what is used on the Info-Ex here and overseas, and because it’s easy to use no matter where you
A final point to consider is how the scale, or resolution of how you define the location can also affect the likelihood rating you end up with. Here’s another example to illustrate it: You have a persistent slab problem which exists only on steep south facing slopes directly beneath the toe of cliff bands. If you choose a broad scale of location such as
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purely aspect -south - you would end up with specific spatial distribution, but if you narrowed it down with your location stated as, "Steep south facing slopes directly beneath the toe of cliff bands." you would end up with widespread spatial distribution. The key to this point is that spatial distribution needs to be considered within the context of the location. I’m sure there are some people who have been doing this all along, but there will also be a few that will hopefully find this useful. If the CMAH is the system you use either personally while recreating, or in your operation then give these ideas a go this coming season and hopefully things will make more sense. If it’s a windslab, it doesn’t have to be specific!
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Moderate Musings Reasons to Become A Forecaster on a Macro and Nano Scale By Gary Kuehn What follows are my observations and contemplations from 2020 as a guide, avalanche educator and keen backcountry skier, mostly in uncontrolled avalanche terrain, and in different mountain ranges each week. Often I found myself traveling in regions without a public advisory or I had left internet coverage before a advisory was published. When this happened I had to create my own advisories with the snow and weather observations I could find and from weather and snowpack links from avalanche centers. My aim in the field is to always choose terrain that I can probe and sense safely in order to confirm or deny my predictions. This season I noticed that when I was in zones with a public avalanche advisory the danger level was often rated MODERATE. Figure 1. The North American Avalanche Danger Scale.
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Globally most fatalities occur at moderate and considerable danger levels, in part because of higher user numbers. Often it's true that if the rating is MODERATE then a persistent weak layer (PWL) is involved. Avalanche forecasters assign a danger level, by considering the expected size, distribution and likelihood of a potential avalanche as well as applying travel advice for each avalanche type. Defining likelihood has been shown to vary on personal interpretation. Familiarity with Figure 1 (see below) and the concepts found in the Statham and McCammon papers (see References) will help in understanding this paper and assist in your interpretation of a public avalanche advisory.
PART 1. OBSERVATIONS AND MUSINGS This section is compiled from my own daily summaries and notes. ITALICIZED Ratings are those from a forecast center and those in regular CAPITALS or in “quotes” were my thoughts: January 5th: LOW TIDE MODERATE, Washington to Montana. I arrived in Montana and all regions were on MODERATE. While driving in I could see it was lean, “low tide” and it looked like New Zealand strength winds had preceded me and stripped many westerly aspects. The structure was poor (end of October snow, two warm and wet periods in November, a December drought, and the occasional gale Westerly during those months). In my opinion hidden objects were a greater risk than an avalanche but I kept reminding myself “If there is enough snow to ride there is enough snow to slide.” January 9th: REMOTELY MODERATE, Montana, Bridger, Madison & Lionshead Ranges. A small (size 1) remotely triggered avalanche was recorded by forecasters from the Gallatin National Forest Avalanche Center (GNFAC). the avalanche occurred in the southern Madison Range. The avalanche danger rating was MODERATE. I thought, “Remotely moderate?" One of the few things I like less than a persistent weak layer (PWL) problem is remotely triggering avalanches. When this happens I often retreat and link turns in non-avalanche terrain or at least a location where the PWL problem doesn’t exist. I associate remotely triggered avalanches with high sensitivity. The size was small and the distribution may have been isolated but everywhere I had travelled (reports from neighbouring states sounded similar) and looked had shown a poor snowpack structure in the early season snow from October and November. January 17th: CURIOUSLY MODERATE becoming CONSIDERABLY MODERATE, Montana, Bridger Bowl Ski Area. Snow is forecast! I’m going to the local ski area where the terrain is mitigated by the ski patrol so I only have to consider storm snow. The danger rating was MODERATE, which I thought was curious because 2.5 cm of snow water equivalent (SWE) fell at Bridger Bowl in six hours. They are known for their very low water content snow but this storm left them with a heavy 30cm of new snow. The ski patrol reported easy ski cuts and never opened the steeper upper slopes on the mountain nor the terrain below these larger avalanche paths. Things had definitely become what I thought of as CONSIDERABLY MODERATE. This was a good
This was a good example of when the differences between a weather forecast and an actual weather event can lead to a different danger rating and occasionally even change the primary avalanche problem. January 20th: SCARY MODERATE, Montana, Bridger Range, Northern Gallatin, Northern Madison & Lionshead Ranges. All regions were described as SCARY MODERATE. I agreed , it was scary! Over the weekend seven human triggered slides were reported, along with several naturally occurring avalanches. Avalanche problems included: persistent slab, deep slab, wind slab, and even a cornice collapse which triggered a slab avalanche. I just finished teaching an avalanche course where we went into two different mountain ranges. Fifty percent of the time we got propagating results on ECT tests and had poor structure. For sixteen of the previous nineteen days, avalanches had been unintentionally triggered by people. With natural and human triggered avalanches, a poor snowpack structure and frequent propagating extended column test (ECT) results, I chose to stay in lower angle, smaller sized terrain with minimal terrain traps. Even still I rode very cautiously that day. January 22nd: WIDESPREAD MODERATE, Montana, Bridger Range and Cooke City. All eight of the GNFAC forecast regions (an area ~ 55 square km radius) were rated as MODERATE. I was in Cooke City for some PWL respite. The snowpack structure there was good, which was very different from the other areas I’d been using for teaching. Digging deeper into the forecast, there was a great discussion by the forecasters of human avalanches still being possible, “Because the consequences of a slide are severe, it is also called "SERIOUS MODERATE, SCARY-MODERATE, SPICYMODERATE, MODERATE-PLUS, or I-DON'T-CARE-IF-IT-ISMODERATE-I'M-STILL-NOT-GOING-THERE-MODERATE.” In short: the likelihood was decreasing but the consequences were not! I was able to relax a little bit in Cooke CIty. Things were still MODERATE, but to me it was a different problem: isolated wind slab that I could manage or avoid versus a widespread poor structure and persistent slab problem that was nearly impossible to avoid. February 2nd: MULTI-PROBLEM WIDESPREAD MODERATE, Montana. Over the previous eleven days the MODERATE danger rating had not changed and the region received new snow in small top ups. The different possible MODERATE avalanche problems had increased dramatically. The advisory mentioned wind slabs, storm slabs, deep slabs, triggering NZAD 31
A skier triggered persistent slab avalanche in Peter’s Creek, Chugach State Park, Alaska, U.S..
other avalanches sympathetically, dry loose avalanches, and cornice failures. I thought: "MULTI-PROBLEM MODERATE." February 6th to the 20th: RESISTANT PLANAR MODERATE, British Columbia - Kootenay, Valhalla, Duffy Lake. I traveled north to Canada where I found a few guides using "resistant planar" to describe their test results. It seemed a bit like sitting on the fence to me with the old difficult to describe fracture character of: "It's not really sudden and definitely not broken, so...it's resistant!" There had been recent warming to high elevations that had created a melt freeze crust. That crust was now buried ~20-30cm deep and I was curious if there was a reactive crust-facet combination present there. I was relieved after multiple ECT's had no propagation's on that layer.
February 15th: SPOOKY MODERATE, Colorado. Sadly, I heard news from Colorado that two out of three snow bikers were killed in an avalanche. From the Colorado Sun February 25, 2020: Avalanche forecasters have tinkered with the moderate description, hoping to warn backcountry travellers that while there may be a low probability of avalanches, there remains a NZAD 32
high consequence in the event of a large, devastating slide. The forecasters at CAIC [Colorado Avalanche Information Center] use the term “spooky moderate” to warn travellers of a high probability of small-to-large avalanches but only on specific slopes. The researchers who studied the slide that killed Block and Almanza-Hernandez said the snowpack that day on the slope above the gully was “quite reflective of a spooky moderate avalanche hazard. In the past seven years, 32 people have died in avalanches in Colorado, 11 of them during periods where the avalanche hazard was ranked moderate. All four avalanche fatalities in Colorado this season have been during periods of moderate avalanche danger." https://coloradosun.com/2020/02/25/snowbiker-avalanchedeath-vail-prepared/ February 26-27: MODERATE, Montana, Bridger Range. I’m back in Montana and they have had significant snow in my absence. The hazard had been rated higher but it was now back to MODERATE. Recently a cornice collapse and a groomer had triggered deeper avalanches in older snow. Older buried facets deeper in the snowpack were still a problem. The likelihood of a deeper avalanche is still low but large consequences are still possible if you were to trigger one so I continue to pick smaller terrain with safe run-outs.
February 29th to March 8th: LOW, Montana, Cooke City.
PART 2. WHAT THIS MUSE MEANS TO ME
I returned to Cooke City where the rating is LOW. My friends had been riding big lines there recently. The snowpack structure is good except on solar aspects where there are a few melt-freeze crusts. After two days of testing I had no propagation around these crusts. The only problem was the ski quality, as some of the zones I wanted to ski required access on sun affected snow. A new risk, other than avalanche danger, is the skiing quality: icy skinning in the morning and a blend of sticky snow or breakable crust until we are low enough to get into consistently collapsible slop. I feel like I have come full circle: I got to Montana two months ago on MODERATE and my greatest concern was hidden objects not avalanche danger. Now I’m leaving Montana on LOW and my greatest concern is for my knees!
Advantages to Being My Own Forecaster
March 12th: WIDESPREAD MODERATE, Alaska, Western Chugach, Talkeetna Mountains. I made it to Alaska and was keen to get out and start observing the snowpack. Advisories for different mountain ranges just an hour north or south from town were on MODERATE and discussed January facets, February surface hoar, recent wind slabs and occasional loose wet and wet slab concerns on solar aspects. “Really again with MULTIPROBLEM WIDESPREAD MODERATE?!”, I thought. I found the snowpack quite variable over a short distance of just fifty metres. ECTs would propagate in the poor structure when a sufficient slab existed and whoomphs in these areas were common but the cracking observed was small at <20m radius. It was easy to trigger small persistent slabs on skis where this poor structure existed but luckily these problem areas seemed isolated. I was touring with a Chugach National Forest Avalanche Information Center (CNFAIC) forecaster. He just smiled and said, “Alaska uses SCARY MODERATE”. Persistent weak layer problems that become buried and lie somewhat dormant, or at least lose some reactivity during the winter, will often reappear with spring warming. Unless Alaska has a sudden spring shed cycle and transitions to a more stable spring corn snowpack I’ll have a BORN-AGAIN SCARY MODERATE on my hands here this spring! As a fellow heli-ski and fishing guide once told me regarding a persistent weak layer high on our concern list that season: “I’ll trust that layer when it is flowing in the river." Thanks to my touring partners who until our recent physical separation had to listen to my musing, many of which gave me feedforward for this article. Also thanks to The American Avalanche Institute, Gallatin National Forest Avalanche Center and Chugach National Forest Avalanche Information Center their resources and forecasters.
I realized that regardless of my role (guiding, teaching an avalanche class, or recreating) and even when I am in an area with a public advisory, I still need to be my own forecaster. Forecasting before looking at a public forecast trains me for when I am in areas without a public forecast or when I leave internet coverage before a public forecast is published. I also realized the advantages I have that public forecasters do not have such as: A) Now-casting. I am forecasting for a smaller area and a known objective, therefore I am able to update my forecast on the go continuously from visual, audible, tactile and intuitive observations during my travels. B) I can reduce the choice of possible relevant avalanche problems through the aspect, elevation, slope angle and timing decisions I make during my travels. C) I am aware of my own risk tolerance and the probabilities I associate with the words used to describe likelihood in public forecasts and my own descriptions. Being my own forecaster trains my predictions, helps keep me alert and builds my intuition. Through contemplation and comparison with other peoples observations and opinions my biases are checked and my geographical reach is extended. I think less about a stand alone hazard rating and more about the big picture by also focusing on: 1. My objectives. 2. The weather forecast. 3. The anticipated avalanche problems and my questions: Is the problem manageable? Is it identifiable? What is the likelihood, distribution, and possible size of an avalanche? 4. Terrain. Can I limit my exposure? 5. My uncertainties and the reasons why. Uncertainty will focus me to acquire observations safely during the day to build a better picture of what's really happening. I can consciously check and update my forecast while moving through terrain (larger scale) and before dropping in at the top of a run (smaller scale) and even adapt while skiing a line down to he choice of a single turn placement (microscale). There are times I have wondered why I skied so "lightly", and conversely if I should have been skiing there at all! This has been reinforced to me on two occasions where NZAD 33
Figure 2: For the public advisory “glancers” are there any adjustments to the hazard scale or public forecasts that might help? UAC forecaster Drew Hardesty suggests adding an “X” (as used in some climbing ratings) to a MODERATE rating when an unmanageable problem exists.
other skiers triggered small avalanches where I had been intuitively skiing 'delicately'. I now use this as a conscious check at the top of a run: “Where could I trigger an avalanche?” Nowadays, if I’ve gotten to the bottom of a run and realised I skied 'lighter' than I anticipated I make sure and communicate that to the others in my group! Uncertainty of Likelihood Drew Hardesty, forecaster for the Utah Avalanche Center, asked a group of winter backcountry recreationists in Salt Lake City, Utah what they thought the numerical probability range of triggering an avalanche was at different hazard ratings. He published the results in his blog entitled: DangerintheDangerRatings,https://utahavalanchecenter.org/blog /15914 The results? Low was rated as a 1-5% possibility of triggering an avalanche; Moderate 25-35%; Considerable 60-65%; High 7585%, and Extreme 90-100%. In his blog Hardesty asks, "What makes up the 25% difference between MODERATE and CONSIDERABLE?" Hardesty addresses concerns that I also find difficult when producing a public forecast, especially describing the likelihood of triggering an avalanche using terms such as: almost certain, very likely, likely, possible, and unlikely. These terms are not clearly defined. A forecast reader could interpret the likelihood of triggering an avalanche consciously by assigning a probability (I suspect done rarely) or unconsciously by associating the word to their previous experiences. issue 38.3 of The Avalanche Review presents eight articles discussing the difficulty in our individual interpretations of probability from the likelihood terms. From one: A study of 75 practitioners from around the world interpreted “Likely” probability of avalanches as a 60% chance (median) and the range was 5-100%! What probability do you, your partners and even your avalanche advisory associate with the terms of likelihood of triggering an avalanche? Are they aligned? Do you ever discuss these terms with your partners? NZAD 34
Unmanageable Problems When writing a public advisory my goal is to accurately communicate a message to a diverse user group in order to educate and assist them in their decision making. Some users will read the details and dig deeper into weather and snow observations. Others will only glance at the forecast to pick up the color, the number, or the single word description of a rating (LOW, MODERATE, CONSIDERABLE, HIGH, EXTREME.) If only a quick glance at the rating is given the actual significance of an avalanche problem can be missed. Not all avalanche problems are created equally. A MODERATE rating can seem innocuous at times, but can actually hide larger, deeper problems from the less aware, or less investigative reader. I often get excited about riding in MODERATE loose dry avalanche problem conditions, whereas a MODERATE deep or persistent slab problem has me looking to avoid it. Persistent and deep slabs are often low frequency but high consequence events. They are unmanageable (without large explosives) and unpredictable but are usually known to be present from the snowpack structure and testing. They are also frequently associated with multiple fatalities within the MODERATE danger rating. A Final MODERATE Thought Whether the forecast is a public one or your own, updating it in the field to the reality you sense and communicating it to others will benefit us all. References Statham et. al. A conceptual model of avalanche hazard; Nat Hazards (2018) 90:663-691 McCammon, Ian & Schweitzer, Jurg A. field method for identifying structural weaknesses in the snowpack, ISSW Penticton, BC 2002 The Avalanche Review 38.3 & 38.4 American Avalanche Association Hardesty, D. Blog: Danger in https://utahavalanchecenter.org/blog/15914
the
Danger
Ratings,
Skidbiter A Conversation With Trev Streat
In each issue of the NZAD we'll feature someone from our snow and avalanche safety community. For our first issue we are lucky enough to feature Trev Streat. When we talked, Trev had just returned from India and was gracious enough to answer our questions while also dealing with some recent health issues. We thank Trev Streat for dropping in first and for taking the time to share some of his story with us all. NZAD: Where did you grow up? What was your childhood like? When/where did you start skiing?
TS: I grew up in Christchurch. I had a pretty happy, normal childhood. I started skiing at 7 years old at the same time as my Dad who had some skier mates who got him into it. NZAD: Where did you ski most back then? TS: Craigieburn Valley and Broken River in the Craigieburn Range. Turkey Heli-Ski with boss Nicholas Clerk.
NZAD: What influenced you to start skiing? TS: I bunked school for a week when I was 8 to ski at Coronet Peak. I was tremendously impressed by the ski instructor lifestyle and I decided that I wanted to somehow ski for life. I went up to Craigieburn Valley as a teenager one year as well as Broken River. I volunteered on the Craigieburn Valley ski patrol for a bit. NZAD: What year was that? TS: 1970 and I started ski instructing at Coronet peak in '77. I went and worked at Craigieburn Valley (CV) two seasons after that as a ski instructor and then went off and did my ski instructors ticket at Coronet Peak - then they sacked me! I then did two or three seasons at CV...just ski instructing. While I was there I got with Mike Perry; CV had hired him to take photos and he got me into climbing. He was a very good mountaineer we actually did a new route on the Hooker Face on Mt Cook first climb together! NZAD: And then? TS: Then I did my Avalanche Level One with Dave McNulty at Temple Basin - it must have been in 1980. I then ended up ski bumming in Chamonix for about 3 winters. I came home in '89 and Paul Scaife gave me a job and I was off! NZAD: How old were you in Chamonix? TS: In my late twenties or early thirties. I started guiding when I was 32. NZAD: For Harris Mountain Heli Ski? TS: Yes. I came back from Chamonix in '89. Paul Scaife gave me a job and I took my Avalanche Level Two in '89 as well. Nick Craddock was supposed to take it but couldn’t for some reason so I sat in for him. My Level Two certification is in Craddocks name! That was also with Dave McNulty instructing and then he was killed in an avalanche while ski guiding. NZAD 36
Shhhhhhhh....'Whisper', a beautiful and safe run just over the Rhotang Pass, northern India.
NZAD: How well did you know Dave McNulty? It seems like he was a man ahead of his time? TS: He was the man. He developed avalanche danger management in New Zealand. I didn’t know him well but he was a good guy. NZAD: How well did you know Paul Scaife? TS: Paul Scaife hired me in 89 when I got back from Chamonix. Paul was really disorganized. I’ve got so many stories about that man, he was a legend. He was a superb guide but sometimes really difficult to work with. Sometimes you’d get everything organised for a really complicated day and then he’d be there in the morning and want to change everything and I’d say “Ok...I quit!” and Paul would be like “No! No! No! No! No!” He was just a lovely guy. NZAD: And he was killed in 2004 while mountaineer guiding?
Trev Streat (red) and client on a pretty good day with Turkey Heliski.
TS: I can’t remember the date...I ended up scraping him up. NZAD: You did? TS: Bad day. NZAD: That sounds like it was an horrific accident. TS: It was a tiny little patch of wind slab, maybe 15cm deep, maybe 10 metres wide. Four ropes and it took two roped groups off of the hill on the way down; they were a couple of guided parties. The other two people survived when their rope got snagged on a piece of ice so they ended up self rescuing but everyone else ended up dead or dying down on the Plateau. NZAD: You don't realize some of the accidents that have occurred over the years and who's involved. TS: There’s a book [Mountain Rescue] that’s got a lot of stuff like that in it by a guy called Phillip Melchior. NZAD: With the accidents you’ve seen or been involved with, do you think this changed your own system or approach to guiding? TS: I think I know more people that have been killed in avalanches than I do by anything else - not to be too morbid. I don't think it changed anything I did specifically but it certainly makes you fundamentally more aware of consequences. NZAD: When Harris Mountain Heli-Ski hired you the NZ heli ski guiding business was booming at that point. Was that the beginning of NZ heli skiing?
"Just about every avalanche or avalanche accident that I have been involved in has happened the first day after a storm."
TS: Nah, I mean it had been going for awhile, AGL [Alpine Guides Limited] had been doing it for I don’t know how long and Scaife had been doing it a few years...things were taking off and there were lots of Japanese skiers showing up then. They were great people! NZAD: When did you get to the IFMGA level? TS: I’d been guiding for Scaife with basically just my Avalanche One qualification
NZAD 37
Powder skiing Nirvana. North facing terrain in the Chandra Valley, east of the Rhotang Pass. Himachal Pradesh, India
and then I got my Avalanche Two qualification during the '89 season. That summer I did my first climbing guides course. Five years later I had my IFMGA. NZAD: How long have you been skiing and climbing guiding for? TS: I reckon I’ve clocked up more than 50 winters heliskiing. NZAD: That's a lot of seasons! TS: That must be 30 in New Zealand, 20 or 21 in India. NZAD: How old are you Trev? TS: Sixty-Two.
TS: There was a Kiwi connection in the Himachal from the beginning because Roddy was a climber and he brought Dave McNulty over to check it out, then it was Craddock and Scaife that went there and then I got in. NZAD: How many operations are there in the Himachal? TS: Just us. There’s sort of one in Kashmir otherwise it's just our operation there.
NZAD: How long have you been writing backcountry forecasts for the NZMSC? TS: Basically since it started.
NZAD: Do you get time off during shoulder seasons or is it winter for you all of the time?
NZAD: What's the one piece of critical information you’d hope someone would take away from the avalanche advisory?
TS: I used to work summers and winters here in NZ and then I got the job in India. I think I started there in about '93. Since then I've clocked up some trips to Manali, Greenland and Turkey too.
TS: Just about every avalanche or avalanche accident that I have been involved in has happened the first day after a storm. Even if things are looking pretty good, it's still a good day to pull your head in.
NZAD: How did you get introduced to northern India and the Himachal Pradesh?
NZAD: How much stock do you put into digging profiles?
NZAD 38
TS: You’ve got to dig if for nothing else just to establish a baseline in the pack. There's times you dig and dig and you think it all looks good and then… NZAD: How has guides training changed since you started? TS: It’s a bit more formal as compared to the early days when it was a bit more rough and ready. NZAD: Do you think people or guides have too much of a reliance on technology in the outdoors these days? TS: High-tech low brain and low-tech high brain. I think it would be stupid not to check out things that might give you an advantage though. I don't know if you’ve heard of a podcast called Freakonomics? NZAD: What is Freakonomics? TS: There's a really good talk on the dangers of safety. It's basically based around research done on American football players noting the players got increasingly dangerous as the protections got better. So they got better helmets and they started using their bodies as human battering rams. They tended to be able to hit harder and it actually made things worse and worse. Along those same lines, I think that the avalanche airbag backpacks are being eyed as the silver bullet for decision making. I can remember when the Avalung came out and sometimes I’d find myself skiing around with it in my mouth and I’d think, “What the heck am I doing?” You have to be careful with silver bullet thinking because none of that is going to stop you from dying in an avalanche. NZAD: Do you think there is technology that might mitigate “bad luck” or poor decisions? TS: I know the one time I was caught in an avalanche I was scared for my life and there was no time to put the Avalung in my mouth. NZAD: Right...or with an avalanche airbag will you actually be able to pull that ripcord? TS: I skied around with one [airbag backpack] all season in India a couple of years ago. I tested it at the start of the season and it worked and I tested it at the end of the season and it didn't go off! The failure rate is actually pretty high with some models. NZAD: Is there any newer technology that you won't ski without nowadays?
Not just avalanches..."Rotor strike to the snow on landing… one of the skids broke through a cavity in the snow tipping the machine forward. The blades came close to entering the cabin…maybe 40cm's above our heads." - TS
"You have to be careful with silver bullet thinking because none of that is going to stop you from dying in an avalanche."
TS: Beacon, shovel, probe. NZAD: Not a lot of change over the years then? TS: Not really, but as another technology example: I’ve spent a lot of time in India the last couple years doing a digital version of our run atlas. You load it up and you’re just a couple of clicks away from your run information. I’ve tried to put in avalanche paths and you can make notes on it as well. That way when someone adds a note you can click on it and see if some area has been tricky etc. It’s no problem for me because it’s all in my head but for others unfamiliar with the place, they can ski around with a cell phone and they can get some
NZAD 39
"There was a notable persistent weak layer that winter. We spent the whole season tiptoeing around!" A helicopter remote triggered avalanche on "Bant Ruar”, Himachal Pradesh, India. The helicopter triggered this while landing on a flat about 300m away below the photographers location.
pictures and information if they don’t know a run that well. It's a good way to pass on your personal experience in order for it to become institutional knowledge. NZAD: Sounds like an amazing project. Seems like all operations could benefit from something like that.
TS: The trick is to make it accessible. Something you can get into and out of quickly. NZAD: Do you think that the health and safety reform in NZ has produced better safety in guiding? TS: No. NZAD: Why not? TS: I probably have a bit of a bee in my bonnet about the state of the safety thing in NZ. I think we’re tending to a culture that's a bit too top down for me. As an example: we had an operations manual, a safety plan, that was a distillation of years of thought and experience which covered almost everything you needed to know. Then the safety folks came in and told us it wasn’t any good and they NZAD 40
gave us five or six little books full of waffle. It really pissed me off...you don’t want to get me started. NZAD: So it's safe to say you don't agree with what has been happening? TS: Well, I don't want to completely negate it. I totally agree that some sort of oversight is necessary, and I'd be interested to see any proof that the new system is working. Part of the problem is that the more onerous stuff that they put on you, the less attention and respect you may have for the real stuff. NZAD: What (if any) “Golden Rule” of safety do you live by Trev? TS: I try to follow Craddock's Golden Rule. NZAD: Which is? TS: Don't Fuck Up. NZAD: If you couldn’t ski guide anymore, what would you do?
TS: I’m about to find out...rather sooner than anticipated. NZAD: Because of your current health conditions? TS: Yes. NZAD: Can you describe what you are dealing with? TS: Basically, I’ve got an inoperable brain tumour. So they will give me some radiation treatment; if I am lucky it will slow it down a bit. NZAD: So radiation won't necessarily get rid of the tumour? TS: No, it would be great if it did, but it's not going to. The clock is ticking. Now when I tell people about the tumour and they say “Oh! Sorry to hear that.” I reply, “Well you’re going to die too mate!” You can either sit in a corner and cry about it or get on with it. NZAD: Can you describe your best day of ski guiding? TS: That would have to be one day in the mid '90’s in Manali. A couple of snowboarders hired the helicopter for a private trip on the last day of the season. The powder was excellent! We rode 16 runs in a big arc around the eastern edge of our regular terrain. After the first five or six runs every line was a first descent and we managed one landing at 5400m in a B2!
Keeping it real after all these years: Trev Streat in the Alpine Guides office, New Zealand.
NZAD 41
PREPARATION
43 Jake Hutchinson - Left of Woomph 48 Professional Perspectives 52 Jack Saunders - One To Remember
Left of Whoomph! By Jake Hutchinson This story first appeared in the February 2020 issue of The Avalanche Review (38.3). “…the preparation for an attack leaves behind cues a trained observer can pick up on to provide an early warning. Training Marines to make those observations was one of the goals of the program. In the lexicon of Combat Hunter, the purpose was to get Marines Left of Bang.” -Left of Bang, Patrick Van Horne and Jason A. Riley
On March 24, 2019, six experienced backcountry skiers were skiing in Cardiac Bowl in the Wasatch Mountains Big Cottonwood Canyon. On their first descent, they observed cracking and sluffing in the new snow as precipitation intensity increased during the day. They chose to follow the ‘traditional’ skin track route back to the ridge. As they broke trail, they observed widespread cracking in the storm slab. As the person breaking trail approached the summit, they triggered a small sluff in the storm snow. As this small avalanche gained momentum and mass, it triggered a larger sympathetic storm slab approximately 200 feet above the lead skier, that encompassed the entire bowl. All six skiers were caught and carried in the slide with two partial burials and one person sustaining a knee injury. Thankfully the party was able to self-extricate and request rescue assistance to evacuate the injured. This accident and many with similar circumstances (obvious clues, improper mitigations) have often intrigued me. Why do experienced and inexperienced people continue to make what in hindsight seem like obvious and easily avoidable mistakes?
"Why do experienced and inexperienced people continue to make what in hindsight seem like obvious and easily avoidable mistakes?"
The full accident report can be found here: https://utahavalanchecenter.org/avalanche/46366) As I crawled down a completely unrelated rabbit hole this summer, studying failure and mindset in the sports performance world, a friend turned me onto the book Left of Bang. This book is based on the Marine Corps Combat Hunter Program, a program to help young Marines identify threats in a world where the enemy no longer wears a traditional uniform and relies on increasingly deceptive tactics to inflict casualties. As I read, and then listened, and read again, I began to see some obvious parallels between patrolling an Afghan market place and working or playing in avalanche terrain. Leave it to a Marine to take a book about identifying and reacting to threats in a non-traditional combat theatre to stretch a few lines, connect some dots, and bring it back home to the mountains. But as I sat reading this book, I couldn’t help but make one connection after another, linking the need for expert intuition and experience NZAD 43
LEFT: Everything that occurs before the avalanche.
PROACTIVE
WHoomph!
between traveling and working in avalanche terrain and going on patrol in hostile territory. As an educator, I have spent a lot of time teaching the premortem: using checklists, identifying the avalanche problem, understanding and assigning open and closed terrain. We teach tools to assess and quantify the conditions under our feet, we explain bullseye clues and give them values in flags and fruit, we warn others of our inevitable human folly and the traps it will likely lead us into - like the Sirens calling sailors to their demise. More recently, we have placed much emphasis on the tour or day post-mortem, whether it was a casual ski tour or an active mitigation day, encouraging honest assessment of how and when we may have been over-exposed and how to mitigate it in the future. But it seems as if we have missed or assumed people were going outside with proper situational awareness. By now, we’re all familiar with the early heuristics work of Ian McCammon and the research on heuristic traps he presented at Penticton in 2002. In fact, I would be shocked if any avalanche course at any level didn’t at least touch on the subject briefly, as it has become such a staple for helping us understand some of the reasons that otherwise reasonable, intelligent people seem to make questionable decisions. By Ian’s own admission, his research was meant as a starting point not the finish line, but unfortunately until recently no one has truly picked up the torch. Like going on patrol in a combat zone, traveling, working, and recreating in snow-covered mountains is a highly complex undertaking, where no two situations are entirely alike; often the clues and cues about what is going on can be deceptive and even conflict with one another. The ability to recognize cues and instigate proper mitigation is critical to both avoiding an ambush and staying out of avalanche NZAD 44
RIGHT: Everything that occurs after the avalanche.
REACTIVE
involvements. The US Marine Corps recognized the need for, and challenge of, imparting experiential expertise and observation into young Marines who would be leading patrols into territory where the enemy was no longer identified by uniform, and often looked no different than the local villagers. They began to look at heuristic cues as a way to help these Marines separate the harmless from the threats, moving Marines from an awareness of danger, to operational and prepared, to appropriately respond. It seemed to me that many avalanche accidents failed to properly take this step in a timely fashion, or that predetermined mitigations were either lacking or incorrect, leading to avalanche involvements. In reviewing avalanche accidents, it seems very rare that people are completely blindsided by avalanches or unaware of the danger around them. Instead, they often identify and are aware of the danger, but fail to make proper mitigations until it’s too late. “Expert intuition: The situation has provided a cue; this cue has given the expert access to information stored in memory, and the information provides the answer. Intuition is nothing more and nothing less than recognition. Valid intuitions develop when experts have learned to recognise familiar elements in a new situation and to act in a manner that is appropriate to it.”‘ - Thinking, Fast and Slow’ – D. Kahneman Expert intuition and how it affects our decision making has been a hot topic of late and is at the foundation of the Combat Hunter Program. The problem lies in experience: how does one install the knowledge and experience of a seasoned vet into a young Marine heading out on his first patrol? How do we share hundreds of days and years of experience and observation in avalanche terrain with those with less time in the trenches? Well we can’t. But we can
provide some tools to help people identify cues and implement pre-determined mitigations and hopefully avoid getting Right of Whoomph. What is Left of Whoomph and how do we get and stay there? Left is pre-event, we are planning and preparing, observing and quantifying. We know the snow holds secrets, we know that steep, snow-covered slopes can and may avalanche and we are in a PROACTIVE state of readiness, looking for pre-event indicators. Whoomph is the avalanche, the event has happened - if you stayed left, you are able to manage and mitigate whatever has occurred. Right of Whoomph is bad: you are reactive and you must respond to a threat to life or limb. You are no longer in control of the situation, and must react to whatever the circumstance requires, whether that is to try and escape an avalanche you are caught in, or rescue a partner. Before we dive into the situational awareness states, let’s talk a little about a part of our brain called the amygdala and how it can both help and hurt us in a response to a stressful event or stimulus. Without diving too far into the medical world, the amygdala is part of the limbic system and it manages all of the systems that keep us alive. It makes your heart beat and your lungs function; it is the primitive part of your brain that takes care of daily business without you needing to think about it. But when we are confronted with threats, the amygdala takes over and puts us in survival mode. That survival mode can take one of three basic forms; Fight, Flight or Freeze. The fight or flight response is well known and in its simplest form, means you either run from a threat (survival by avoidance) or you confront it (survival by confrontation). Each situation is different and either of these responses may be the correct or incorrect mitigation given the circumstance. The third response, Freeze, is bad. This is the amygdala hijack: your heart rate, adrenaline, and other factors conspire to make you the proverbial deer in the headlights. You are a liability, unable to function and likely have become an additional threat or condition that requires mitigation. This will be known as Condition Black. SITUATIONAL AWARENESS STATES Retired Marine Lt. Colonel Jeff Cooper developed a color coded system of awareness during his time in the Vietnam War to describe the psychological conditions a person could experience during any given situation. His scale used four colors, white, yellow, orange and red to describe the range from unprepared and unaware at one end, and “in the fight” at the other. The Combat Hunter program added a fifth color, black, to describe the freeze. From here I began to
apply these concepts to situational awareness in avalanche terrain and will describe them as follows: CONDITION WHITE: White represents ‘Ignorance is Bliss,’ where you as skier or soldier are unaware the world is dangerous and unprepared to take action if a threat presents itself. Your physical state is relaxed and vulnerable. This could be the resort skier venturing outside the boundaries, a young ski patroller, or the backcountry enthusiast with headphones in and lacking focus on the environment around them. CONDITION YELLOW: Yellow represents optimal operational function. You are aware the world is dangerous, you know avalanches exist, you’re likely to have an idea of what type and where they exist, and you are psychologically prepared to do something. You have assigned cues that may elevate your state to Orange, but haven’t seen a specific indicator yet. You are observing, assessing, and quantifying the world around you. Physical state is relaxed, yet ready to react if cues present themselves. CONDITION ORANGE: A cue has presented itself: you are now aware of a specific threat – crossing a slope, beginning a ski cut, or opening a run come to mind, but you aren’t so focused on the specific threat that you have become oblivious to the world around you; you are still prepared to assess and mitigate additional threats. Your physical state has changed: heart rate and respirations have increased due to adrenaline. You are no longer relaxed, you are ready to take actions. Rescue, escape, and avoid are on the table. This state isn’t sustainable physically or mentally, but once the threat is mitigated, a return to yellow is possible. You are poised, left of Whoomph, anticipating some action. CONDITION RED: Fight or flight time. The shit has hit the fan and you are completely committed to the emergency at hand, both physically and mentally. Your instinctual and emotional responses to stimulus have been heightened, while your intellectual responses have been lowered. Time distortion is also likely to occur. The amygdala is taking over and prioritizing your resources to the systems that keep you alive. Physically you have likely experienced an adrenaline dump and your fine motor skills (think dexterity, hands and fingers) will disappear. You have no opportunity to go back down the scale until the threat is fully mitigated. You are now right of Whoomph. CONDITION BLACK: If red is bad, black is its scarier and meaner big brother. You have experienced a complete mental and physical breakdown. Full amygdala hijack has occurred and you are overloaded. You’re in denial and confused, likely irrational and may become repetitive. NZAD 45
PHYSICAL STATE
MENTAL STATE
WHITE YELLOW ORANGE Unaware of environmental danger Unprepared to take action Oblivious
Relaxed Vulnerable
Prepared and alert Proper situational awareness, yet no specific threat has been identified
Alert to a specific danger or condition Still aware of surrounding environment
RED Fight or flight mode Complete commitment to emergency at hand Instinctual and emotional responses heightened Lowered intellectual response Time distortion
BLACK System overload Denial Confusion Irrational and/or repetitive
Observing and quantifying
Prepared to assess additional threats
Relaxed but prepared to react
Ready to take action
Adrenaline dump
Adrenaline overload
Rescue, escape, evade
Fine motor skills disappear
Cramping
Heart and respiratory rates increase
No chance to lower situational state until threat is mitigated
Ready to shift to "ORANGE" as cues present themselves
Hyperventilation Gross motor skills affected
COMMENTS
Freeze state
Ignorance is Bliss
"I may encounter avalanches today."
Physically, a total adrenaline overload has occurred, gross motor skills (walking) have deteriorated, cramping and hyperventilation may occur. Now you cannot and will not fend for yourself and will require caretaking and/or evacuation. Operationally (whether that is avalanche work or recreational) it seems obvious that yellow is the appropriate and desired state, white has no place in avalanche terrain, and moving to orange is likely to occur, but this is a manageable state. Avoiding the red and black is critical to staying safe. So how do we appropriately add this to our already bursting tool box? A core tenet of the Combat Hunter program is to “Establish the baseline, and seek anomaly,” which is the foundation of appropriate situational awareness. Condition Yellow represents the baseline. Being in Condition Yellow doesn’t hurt. You can and probably should live there most of the time without a lot of stress. Condition Yellow is not being paranoid, it’s not jumping at everything, it’s just being alert. One benefit of Condition Yellow is that it actually allows you to go out and safely and happily engage with the world. It allows you to maintain your intellectual curiosity and your love of fresh air, mountains, snow, and skiing. If you travel the mountains in Condition White, you’ll wind up overwhelmed, shell shocked, and possibly dead. Condition Yellow and the baseline are established in a variety NZAD 46
Ski cutting, opening a slope, rapidly changing conditions or baseline is wrong.
You are right of Woomph! Reactive to situation.
Complete amygdala hijack You have become a victim
of ways and means depending on the application, but for a user, the local avalanche bulletin, a knowledge of season history, pattern recognition and specific avalanche problems are the building blocks. Baseline is enhanced with partner discussion, route planning, and checklists. For the professional, this also encompasses the AM meeting, previous day’s observations, and the Operational Mindset. The next step is to identify the cues that warrant an elevation to Orange – performing a ski cut or opening a slope, specific environmental cues – cracking, collapsing etc. Rapidly changing or unexpected conditions (test result not in-line with baseline – aka anomaly), specific group dynamics or even injury. The final critical step is assigning proper mitigations to each cue – to keep you in orange and avoid red – but also to describe conditions or cues that allow you to move back to yellow. So what about that anomaly part? Most avalanche accidents don’t seem to be caused by anomaly, but rather a failure to either identify the cue or to apply improper or untimely mitigation – which could be considered an anomaly itself. A few other anomalies that come to mind include time lag, perception bias, and those well documented heuristic traps and other human factors. How do we avoid the red and black? Well we could stay home, out of the mountains, and live in a bubble, or we could look at our training and how it’s deployed. It’s incredibly
hard to accurately re-create the stress of an avalanche event, but by training as close to reality as possible, we maximize our ability to stay in orange. Knowing rescue gear functions upside down, backwards and sideways with your eyes closed and sirens going off is one way to mitigate the loss of fine motor skills. Until faced with a situation, no one knows how they will respond, and previous response is no guarantee you will function in the red and stay out of the black. The goal is to make everyone an avalanche expert and make them so adept at identifying and understanding specific avalanche conditions, they begin to do it intuitively. This looks like creating the ability to be hyper aware of the obvious threats while still analyzing the external complex world. Achieving this level of expertise requires thousands of focused hours in the mountains. Once we understand the differences between the novice and the expert we can devise systems to help close the gap and assist novices in gaining appropriate experience. Research psychologist Gary Klein cites the following as abilities experts have that novices do not: 1. Experts see patterns that novices do not detect. 2. Experts see anomalies – events that did not happen. 3. Experts see the big picture (situational awareness) 4. Experts create opportunities and improvisations. 5. Experts have the ability to predict future events using previous experience. 6. Expects see differences too small for novices to detect. 7. Experts know their limitations. Finally, as we send novices out into the mountains, we must remember the ‘wicked learning environment’ where the novice will often lack direct feedback to help them assess the accuracy of their observations and conclusions, which limits the value of the experience and may assign incorrect values to the observations. Mentors can be a valuable asset here, to help the novice understand when they made good decisions, or just “got away” with a bad one. Back to Cardiac Bowl. It is my conclusion from reading and listening to first person accounts, the group was correctly operating in Condition Yellow, aware of the specific danger for the day and how it was forecast to change. They observed and identified cues to support the baseline and appropriately moved to Orange. The mitigation (increased spacing) turned out to be incorrect due to an unexpected anomaly. The possibility of triggering an avalanche was identified - the anomaly was the size: the entire bowl sliding meant everyone was in harm’s way. Luckily no one was killed or seriously injured.
How do we impart this expert knowledge into the novice for future use? It’s quite simple – in the face of rapidly changing conditions and obvious clues of instability, margins must be widened and rather than spacing, the appropriate mitigation was to choose the longer, less direct, and less exposed up track. The greatest failure of accidents is to not objectively learn from each and every one. In conclusion it's a simple process: 1. 2. 3. 4. 5.
Identify the baseline. Identify the threats and assign cues. Assign mitigations for specific cues. Be wary of anomaly. Stay left of Whoomph.
Sources: D. Kahneman, Thinking, Fast and Slow. Klein, Gary, Sources of Power: How people make decisions. Patrick Van Horne and Jason A. Riley, Left of Bang. Gavin DeBecker, The Gift of Fear. Michael Syed, Black Box Thinking.
Click here to check out the NZAD website! You'll find great links to other snow and avalanche safety resources and older issues of the NZAD. NZAD 47
Professional Perspectives
We'll be featuring snow and avalanche professionals and recreationalists as often as possible in NZAD. We think its very important that our community gets an opportunity to get to know each other, share ideas, and discuss conditions and preparations. To that end we asked some of New Zealand's snow and avalanche pro's a simple question for Issue One:
What do you do to prepare for the upcoming winter season? Note: At the time of publication the ongoing Covid-19 lockdown could hinder or halt many of the northern hemisphere professionals featured here (outlined in red below) from assuming their safety roles in New Zealand. As a result some of the names and titles may be different during the 2020 season and NZAD apologises for any discrepancies.
Tim Rogers Ohau Ski Area, Snow Safety Officer UDOT Avalanche Technician, Utah Arriving to a New Zealand winter from overseas has its advantages and disadvantages. Advantages include that I’m fresh off months of assessing snowpack, while disadvantages include usually playing catchup, with snow already on the ground and a thin, weak snowpack with plenty of layers to assess. For me, there’s really no other way to get a grasp of conditions than to get in the snow and start digging. I’m more of an extrapolator, so if I can get a handful of pits and stability tests on a number of aspects around the field, I can quickly get a picture of where suspect crusts and old snow are distributed. Tap tests can give you some clues as to how the snowpack might react under the load of a skier or approaching storm, but the early season is also a great time for explosive testing. Wind slabs can be stiff and I’ve learned not to underestimate just how keen our early season skiers are, so where there’s a ribbon of snow threading the rocks you can bet it will get skied. A couple of shots throughout the field can indicate where further work might be necessary and also help prevent the public from kicking off a small pocket that might send them into a pile of rocks. My goal is always to get as much of the field open as quickly as possible, so skiers can get spread out and start cutting up any potential weak layers, and so we can all get to work doing what we love best!
Anna Loomes Alpine Guides Operations Manager Organising weather and avalanche forecasting resources is a key part of my preparation for a winter of ski guiding. I have a folder of web pages for each region; Methven, Mt Cook, Craigieburns, Niseko, Furano... In autumn, I pull out the appropriate folder(s) onto my bookmark toolbar for easy access. The pages are finely tuned and specific: MetService, infrared satellite, isobar map and national park forecast. Windy.com has the pin set in the most useful location. Avalanche.net.nz opens to the relevant regional forecast. Login details for remote weather stations, Infoex and the operation’s shared files will be checked. A scout takes place across colleagues and the internet to hunt for new or better sources. Rainfall data is available to the public through sites such as Ecan. Strategic webcam locations are part of the list, especially for heli skiing. And reports from surrounding ski areas. From the region’s bookmark folder I can ‘open all in tabs’ and my browser will fill up with all of the current information. A Storm Log with notes about early season weather and snow events allows me to form a history of the snowpack. When we get on the snow, I can find the rain crust which formed after the first big snowfall or look out for a facet layer that was likely to have formed during the long fine spell in late June. The data will be combined during the winter with lots of observations and discussion with the team and wider mountain community. The aim of all of this is to learn, stay safe and find the best possible skiing. NZAD 48
Connor Glynn Mount Hutt Ski Area, Snow Safety Officer MSC NZAA Forecaster, Mount Hutt Region My early winter programme usually involves avoiding facing the reality old man winter is back again and trying to squeeze in as much down time as possible. Having said that I’m very fortunate to begin working in the mountains early doors, usually the middle of May. This allows plenty of time to begin to wrap my head around and try to understand what the snowpack (if any) is doing. Initially this begins with bashing around on rock trying to sort ridge line signage when the weather allows. While this may not give me a great understanding of snowpack structure it’s a great opportunity to give myself the ability to get eyes on all our terrain safely. With the operational stress of getting a larger, commercial mountain up and running I find it’s very important as the one responsible for Snow Safety to try and stay focused on exactly that. With further on-snow travel generally possible by late May, getting out and about and gathering as much information as possible is key. Carrying out snowpack assessment, testing and beginning to form an understanding is hard with the small timelines available but a strong team helps hugely! Getting 12 sets of eyes on the snowpack and talking things through as a team is often a great way to come to early season conclusions. This is also a great chance for the team members coming off a summer to blow out the cobwebs and get heads out of the surf and into the snow. Fingers crossed for a 2020 winter!
Irene Henninger Remarkables Ski Area, Assistant Snow Safety Officer I start out by observing any pre-existing snow that is already on the ground, its aspects and elevations, and any metamorphism which may have occurred based on the weather history. At this point I also ensure that our weather stations are operational so that continuing weather observations can be made in regards to the transformation of the pre-existing snow and any new precipitation that arrives. As a team, we then start gathering information. By taking daily weather observations we develop a picture of the snowpack as it evolves throughout the season. These observations are entered into the Info-Ex where we can share information with other operations. Information sharing is a vital part of avalanche forecasting and discussing observations and results with nearby professionals can go a long way towards enhancing our own forecasts. Once we’ve made our preliminary assessment of the snowpack, the team gets out into the field to test our analysis. Pits are dug and stability tests are completed to check for layers of concern and potential hazards either at present or in the future. If there are initial concerns, such as basal faceting under new snow, the field check may begin with slope testing using explosives or ski cutting. Any new observations or results from the field then get fed back into our understanding of the snowpack, contributing to our future forecasts and decision making. This feedback loop, which is grounded in early season observations, is a critical part of my forecasting strategy throughout the season.
Aaron Barnett Mount Cheeseman Ski Field, Snow Safety Officer Weather is the architect of the snowpack. Weather events ranging from precipitation, wind, and even the dreaded high pressure will determine how a seasonal snowpack develops instabilities or gains strength throughout the season. As a result, my preseason process often begins with an obsessive search for as much weather data as I can find. By the time of my first forecast my attention to the weather has become a compulsive habit. With this foundational knowledge I can begin to hypothesize how the snowpack is forming. The rest is just skiing around to gather data to support or disprove my hypothesis.
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Ryan Leong Whakapapa Ski Area, Snow Safety Officer MSC NZAA Forecaster, Tongariro Region Over summer I keep my head in the snow by listening to podcasts, (the Utah Avalanche Center podcast is great) reading articles and publications such as the avalanche journal. During preseason work the first things I do are read the previous year's snow safety report and review our avalanche risk management system - the documents which outline how we manage avalanche risk. Doing these things is a good way to start thinking operationally again, check over things that worked well, things that didn’t work so well, and adjust them as needed so we hit the ground running when the snow falls. In the field I get out and see where the snow is sitting. What paths are at threshold? Or if not at threshold, how far away are they from reaching threshold? Then we know when to start doing avalanche control. There is usually a window of time where we don’t have enough snow to open for public skiing, but there is enough snow to create avalanche risk for the staff that are moving around. Things take a bit longer at this time of year because we don’t have the same ease of access with groomers and snowmobiles that we do once we are into the operational season. So this involves a bit of walking / ski touring around to keep an eye on conditions that could present problems in the short term (wind slabs etc), as well as watching for conditions that cause headaches later in the season (developing persistent weak layers). The other key preparation process is to try and set up for success with a solid training program for the snow safety side of the operation. We have a small team for the amount of avalanche terrain we have to manage, so the more prepared and engaged we can be the better it works out when storms are rolling through and the hazard is up.
Bob Miller Administrator, Canterbury Ski Touring Facebook Page I like going to any of the avalanche evenings run by various outdoor stores. While the information is generally a repeat of things I have heard in different courses and in my readings, there are always one or two new things I pick up. I watch the weather specifics from the first sniff of snow right through winter. Information about types, amounts and direction of precip, along with temperatures is helpful to understand how the base of the snowpack is setting up. Once the avalanche forecasts start, I read these for all the areas I am likely to tour in. I am in the hills all the time, well before there is a skiing base and I note the temperature of the rocks, the type of snow that first falls, how temperature and additional precip bonds with it and compare that to the picture I have put together from the other sources. I constantly test the snowpack by hasty pits, snow pole or ice axe poking and boot kicking. As soon as there is enough snow to ski, I use extended column pit tests to assess collapsibility of the slope and watch ski jump tests and general skinning to gauge propagation of slopes. Once snow professionals begin their work, I talk to them extensively about their opinions. I take all other opinions with a pinch of salt, having seen how some people observe and report snow conditions.
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Mike Lynds Cardrona Ski Area, Snow Safety Officer When I start back up the hill after a long summer of BBQ's and bikes I jump back into the avalanche world headfirst to try to get a handle on things again. I spend time reading and reviewing notes from the previous season which I have left myself in an attempt to carry the momentum over from the previous season. I catch up on any noteworthy events from the northern winter - their avalanche journals are a great resource for doing this. I have the luxury of starting up the hill early, so I’m often there as the first decent snow of the season falls. I try to keep track of what’s falling and how things are developing, but the early season snowpack has its challenges. Often just navigating the hill on skis to check things out can be more hazardous than the risk of avalanches itself. Shallow, faceted snow on rock and tussock, breakable crust, track pack and death cookies are all negotiated after not having been on skis for 6 months. This is often not a graceful return. Digging pits and carrying out active control work on paths as they come online for the season starts to paint the picture of how the snowpack is developing. I’m most cautious early in the season: the snowpack is unmodified, shallow and cold, and the team are still getting back into the swing of things. In the end, explosives are a great tool for testing theories and the snowpack.
Leigh Frye Avalanche Technician, Big Sky Ski Area, Montana I treat most avalanche terrain as unstable until proven otherwise. On ski patrol we have the benefit of testing slopes with explosives before exposing ourselves to any potential avalanche hazard while digging pits, probing around or skiing across terrain. Precipitation, temperature and wind sensors are huge in remote forecasting what might be happening in the mountains. I rely heavily on this data in making operational decisions for ski resort terrain/roads/staff and public use as well as forecasting in the backcountry. Synthesizing this remote data with hard field data (pits/field obs/explosive tests) is done by seeing what information correlates to each other and what doesn’t. I am constantly reassessing that correlation and double checking what makes sense in my mind and when things are not adding up then figuring out why. It could be poor remote information like a rimed weather sensor or maybe bad field data like a poor pit or explosive test location. Getting out there is what I love and works best for me. Changing between continental and maritime-ish snowpacks can often involve a slight change in mindset and avalanche problem. I am looking for Type 1 information or red flag signs of instability like recent avalanches, collapsing, or cracking around my skis. I am looking for this information because it is most important to me for personal safety and may allow or deny me access to snowpack and terrain to ultimately generate an operational or public forecast.
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ONE TO REMEMBER By Jack Saunders
A size 2.5 slab avalanche triggerd with explosives on Bluff Face, Porter Heights July 2017. Large grained facets and depth hoar are clearly visible atop the failure plane of older snow and frozen earth.
In July of 2017, the Craigieburn Mountains in Canterbury experienced a depth hoar avalanche cycle that lasted for several weeks. As the ski patrol director at Porters Ski Area that season, I was in a unique position to watch this snowpack develop and eventually avalanche. The season began similarly to others, with June snowfall blanketing the range with roughly half a meter of snow. But an extended period of unseasonably cool temperatures hit us at the same time, and lasted into July. The shallow, weak snow structure combined with a strong temperature gradient to form depth hoar rapidly. This structure existed from 1,700 meters to ridgetop on the north aspects and extended nearly to the base area on our shaded south through east aspects. Depth hoar is among the most concerning persistent weak layers, alongside surface hoar, facets and hard crusts. Avalanches involving depth hoar are difficult to forecast and often deadly. These were the perfect conditions to create depth hoar: Less than a meter of early season snow that doesn't melt away, and cold, clear air temperatures. Because the temperature of the rocks and earth below it remain near zero, it creates a steep temperature gradient within the snowpack. With that comes a steep vapor pressure gradient, which means the water vapor moves quickly between grain forms and create sharp angular crystals that bond poorly to each other. This creates a shallow, loose and sugary base for the rest of our winter storms. This snow by itself is not a hazard, but with a slab of snow above it, it becomes a predictably unpredictable weak layer capable of producing massive avalanches deep into a winter season and occasionally reactivating in the spring as large, deep wet slab avalanches. I was on edge. We pushed Porters’ opening day back to July 7th, due to low snow coverage on the lower mountain, opening on a solely man-made surface with just the lower mountain and beginners area. On July 6th, we conducted initial avalanche control routes on our south through east aspects, where there was just enough snow on the ground to navigate on skis. The snow near the ridge-top was firm and scratchy in spots, and hollow and punchy in others. On open faces or avalanche tracks, the snow became less supportable, and we could hear the faceted snow crystals hissing under our ski bases as we “combat skied” through them, occasionally snagging sharp rocks. With little snow in our start zones and no results with explosive testing, our patrol felt good about opening the lower mountain at the bottom of the avalanche tracks the following day. The twenty to thirty centimeters of initial June snowfall hung on in the shaded aspects of the upper mountain until several millimeters of rain fell on July 1st. This rain event capped the thin and faceted snowpack, inhibiting vapor transport,
which allowed the faceted grains to metamorphose into even larger and weaker striated facets, which continued to develop into depth hoar. The fifth day of the operating season, ten days after the rain, thirty centimeters of snow fell at the weather plot in the base area near our first aid room. This new snow was the first actual load the June snowpack had received since it had been capped with the rain crust roughly ten days previously. The snowpack more than doubled overnight. The ski patrol set out that morning armed with explosives, intending to run full mitigation routes across the mountain and have our lower mountain open to skiers by late morning. By headlamp, another patroller and I hiked north up the ridge to the summit of the ski area, Allison’s Peak. Another pair of patrollers on an adjacent route threw the first explosive on a more easterly aspect. Over the radio, they reported a long and deep crack had formed, but the slope didn’t avalanche.
Above and below: Advanced facets and depth hoar at the failure plane of the Bluff Face avalanche.
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Bluff Face from the base area of Porter Heights, July 11, 2017. As the first storm of the operational season approaches you can see where old rotten snow from June was located on the mountain (pretty much every start zone). Overnight the upper mountain picked up 30cm of new snow.
Shortly after, my route partner and I threw our first powergel from the top of Bluff Face. The explosive round detonated near the top of the 38-degree southerly face, releasing an old snow avalanche that propagated across multiple start zones and ran nearly to the groomed terrain at the bottom of the path. A significant result! The control team on the easterly route soon after triggered a persistent slab avalanche in a more confined gully that ran the full length of the path. No other avalanches were triggered that morning, however some of the explosives thrown produced long, deep, traveling cracks, including one that was 15 centimeters wide.
across the entire road, which I later measured at 660 meters long. That crack showed me the propagation propensity of a buried persistent weak layer like I have never seen before.
With results like this, I kept the mountain closed that day. It was a hard decision to make, but in hindsight, it was a good one.
Should we trust that snowpack? The reality with depth hoar is that once it’s formed, you have to work with it, because it’s not going anywhere anytime soon. The deeper the depth hoar layer gets buried, the more difficult it is to trigger with explosives or as a skier. Even when depth hoar is buried by a slab of snow many meters deep, terrain features (like on the sides of big faces or near rock outcrops) can cause it to be less than a meter from the surface, meaning a skier could influence it with their weight. Unfortunately, the deeper it’s buried and the more difficult it is to trigger, the longer it will propagate and the deeper and more destructive the avalanche will be.
In an effort to more thoroughly mitigate the avalanche hazard and in preparation for opening for the next day, we rearmed and returned to the south face to clean up some lingering hazard. Instead of hiking to the summit like we had hours before, we opted to take the traverse from McNulty’s Saddle to Bluff Face known as Adrian’s Highway. The ridge to Allison’s Peak was scoured back to the July 1 rain crust, and we felt good about skiing underneath the ridge start zones. But an upslope wind had scoured the ridgeline and left a 150-centimeter drift on the leeward side of the road crossing the face, Adrian’s Highway. As soon as we moved out from the saddle onto Adrian’s Highway, we heard the loudest collapse, or Whoomph! I’ve ever heard. The road hadn’t been groomed for the season yet and was not compacted. We saw the crack that formed during the collapse and followed it NZAD 54
One of the more difficult aspects of forecasting persistent weak layer avalanches, specifically depth hoar avalanches, is the fact that this snow structure is present throughout the entire ski area, and in this case, the entire region. We got a 30-centimeter storm, two avalanche paths actually slid, and most of the others cracked. But could we now trust them? What if we only got a 15-centimeter storm and no avalanches on control?
With the lack of pre-season snow present on our upper northerly aspect, along with multiple heavy-hitting explosive routes, we felt comfortable opening Big Mama on our more northerly aspect a few days after producing the deep persistent slab avalanches in the southerly and easterly
Skier triggered wind slab avalanche in closed terrain at Porter Heights, July 2017. Two members of the ski patrol are visible in the upper right corner. The inset (same photo) is for scale and shows where the avalanche crossed the access road to Bluff Face.
aspects. Shortly after this, a small storm rolled through the region from the southeast, dropping twenty centimeters of new snow. Full avalanche mitigation efforts produced minimal results, and we had the ski area open by late morning. The snow had stopped by the time we opened, but the loading was just getting started. By late morning, the winds had shifted 180 degrees to the northwest and grown stronger, causing rapid loading in areas that earlier that morning had been either bare or wind stripped back to the July rain crust layer. Our southeast aspect of the north ridge received one to two meters of new wind transported snow in a period of about three hours. That’s rapid loading! So rapid, in fact, the ski patrol didn’t notice it. This loading happened specifically on that portion of the ridge in our ski area, while other similar aspects remained virtually unaffected. Because of our concerns with the persistent weak layer and the new snow on the mountain, the ski patrol had established a hard rope line closure at McNulty’s Saddle, closing off all access to the upper start zones on the southeast aspect. Unfortunately, a group of four skiers had left the ski area boundary and ventured into Crystal Valley, a large alpine basin north of Porters. The group, led by an IFMGA guide, triggered a sizable D3 avalanche that failed on the same layer of depth hoar we triggered avalanches in the ski area. They retreated back into the ski area boundary, staying on top of the broad ridgetop leading back to McNulty’s Saddle until about halfway down the ridge. The wind had blown all the snow off the ridge down to rock, and
the guide skied around a protruding rock formation off the ridge and onto the newly formed snow slab within the closed area of the ski area. As she moved from the ridge to the slope, her weight remotely initiated another size 3 avalanche, this time in the ski area. Experiencing a large avalanche triggered by a skier within my ski area, albeit in a closed area, was a terrifying experience. Riding up the lift system to access the avalanche site was gut wrenching. As I sat on the slow moving fixed grip chair lift I could clearly see that the crown was over 200 meters wide and at least a meter deep. Coordinating a response over the radio and listening to the patrol team communicating where they were and what they were doing calmed my nerves by the time I reached the top of the third T-bar at the top of Porters. Thankfully, the patrollers on the upper mountain were on site immediately and able to do a hasty search and interview the witnesses and effectively clear the avalanche accident site before I arrived on the scene. A great outcome for an unfortunate event. This snow storm and associated wind event caused large avalanches throughout the region, both in the backcountry and during avalanche mitigation. Other ski areas also experienced post-control avalanches. Given the unusual conditions, it was lucky no one was significantly injured or killed during this cycle.Another week passed, and Porters received a moisture-laden storm driven by southeastern winds that started as rain and ended with well NZAD 55
Propagation propensity anyone? A very long crack, triggered by a groomer, extends for hundreds of metres across Stellar Bowl, Porter Heights, 2017.
over a meter of snow at our base area. This was enough load to naturally avalanche our remaining weak snow while the ski area was closed. Using extensive helicopter bombing, we tested the new snow load left behind and got minimal results. After this storm, we opened all the terrain in the ski area and had no additional persistent weak layer avalanches that season.The most important attribute of a persistent weak layer is its persistence. These layers can be present in the snowpack for the entire season, and the longer and deeper they’re buried, the more deadly and destructive the avalanches they initiate become. This is because depth hoar is formed near the ground, and when it fails, the avalanche it releases contains the entire season’s snowpack. These conditions create a snowpack that can sometimes hold the weight of a skier, and sometimes many skiers, which makes a slope with many tracks look that much safer, when in reality it could be ready to release—just waiting for someone to ski over the specific trigger spot. If you're a backcountry skier or an avalanche professional, my advice to you is this: Pay attention to these layers if they develop in your area. Pay attention during the course of the season, and watch where snow sticks around before it becomes buried. When you get out on the mountain, use your shovel. Dig a hole, and identify where these layers are distributed across the mountain, both in terms of aspect and elevation. Test their strength and propagation propensity with tests like the Compression Test, the Extended Column Test, the Deep Tap Test, and the Propagation Saw Test. And read the daily avalanche advisory for your area from the Mountain Safety Council (avalanche.net.nz). When a weak layer is present, take a conservative approach by using heavy and excessive mitigation efforts, or if you’re a recreational backcountry user, stick to lower angle terrain where you’re less likely to trigger an avalanche. Stay alive today so you can ski again tomorrow. NZAD 56
Knowledge is Power
TRAINING AND EDUCATION
58 Francis Charlesworth - NZAC Pathway 60 Ben Corcoran - Vocational Educational Reform 61 Peter Bilous - Otago Polytech Updates 64 Bob Miller - SlowSkinners
The NZAC Snowcraft and Mountaineering Pathway By Francis Charlesworth The New Zealand Alpine Club has been a voice for climbers and mountaineers across New Zealand for the last 129 years, that’s right, the club was founded in 1891. Since then, the club has evolved into the organisation it is today with over 4500 members, huts spread across the country and a range of publications including The Climber Magazine, The Alpine Journal and a steady stream of quality guidebooks. Education in the climbing, mountaineering and ski touring fields is another fundamental part of what the Alpine Club offers to its members. This has been delivered for many years utilising experienced volunteers for instruction delivered by local sections and NZMGA Guides for our national instruction programme. These instructional courses have proved to be extremely popular in recent years but our members felt they lacked a clear pathway as to how they could progress from being introduced into the alpine environment (typically through a section lead snowcraft course) through to other NZAC courses and then becoming a mountaineer capable of taking on New Zealand’s 3000m peaks. In response to this, the NZAC has developed its Instruction Pathway for Snowcraft and Mountaineering. The NZAC Snowcraft and Mountaineering pathway starts on a local level, with many sections running multiple NZAC Basic Snowcraft courses each winter. Along with Avalanche
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Awareness Courses and Basic Navigation Skills Courses, these courses focus on taking new participants into the mountains to gain skills, confidence and experience in thealpine environment. Someone who has completed all of these courses (or already has the skills detailed in the course outcomes) should have the skills necessary to travel on Mount Cook Grade 1+ Terrain. The second tier of the pathway is accessible for those who have consolidated the skills learnt through the first tier. It’s important to note that people can gain these skills through a variety of means, not only through NZAC courses. Learning from experience friends and mentors is often a great way to consolidate skills and further your knowledge. Likewise, there are many companies across New Zealand who run excellent mountaineering courses which may suit your needs better. For people looking to take their mountaineering to the next level, local NZAC sections run NZAC Intermediate Snowcraft Courses throughout the winter alongside Intermediate Navigation Skills Courses. The Backcountry Avalanche Course is run nationally throughout the winter. Having completed these courses (or gained the skills taught elsewhere) and consolidated the skills, people should have the skills and knowledge to travel on Mount Cook Grade 2+ terrain (non-glacial).
The final progression of the NZAC Snowcraft and Mountaineering Pathway is to work towards becoming competent to travel on glacial terrain and climb technical mountaineering routes. Significant consolidation of the skills learned in the intermediate tier of the pathway is required before progression onto the advanced courses. With a rockclimbing background (sport or trad) and the skills from the intermediate tier of the pathway the next steps are to attend the NZAC High Alpine Skills Courses (run nationally each summer) and the NZAC Leading on Technical Ice Course (run nationally each winter). These skills combined with ongoing avalanche training through the Backcountry Avalanche Refresher Course complete the pathway. Members who have completed these courses (or have the equivalent skillset) are classed NZAC Advanced Mountaineers and are likely to be comfortable travelling on Mount Cook Grade 3 and above terrain. Once people come out the end of the pathway the NZAC hopes that these people will be able to mentor and support others who may be looking to progress their mountaineering skills. Consolidation of learning is key at every step of the pathway, simply attending course after course is not enough. The courses should be seen as a first step in gaining new skills. Participants will be left with a clear indication of what their skill set is, what their next steps are and how they can consolidate their skills through enjoying and travelling in New Zealand’s Mountains. The real learning happens after the course has been completed! The NZAC hopes to be able to run a selection of courses over the coming winter although much of this is on the drawing board as we look at how COVID-19 will impact our delivery. Keeping up to date via the NZAC website, social media and our newsletter is the best way to find out when our courses are confirmed. NZAD 59
The Reform of Vocational Education in New Zealand By Ben Corcoran, Skills Active Kia Ora - Over the last five years, Skills Active has been looking after the transition of professional avalanche qualifications on to the New Zealand Qualification Framework. This effort has meant formal recognition for these qualifications as the national standards, and has secured ongoing funding pathways for tertiary providers. The government is now commencing a total restructure of all vocational education provision and, although the actual qualifications will not change, their management and delivery will. The oversight of qualifications will pass to new organisations called Workforce Development Councils (WDC). The job of each WDC will be to advocate for workplaces, to ensure that qualification content and delivery meets the needs of its group of industries.
The timeline for this all to be up and running is 2023. TEC has not yet indicated that there will be any change due to Covid-19, but we will keep you posted. In the meantime, itâ&#x20AC;&#x2122;s business as usual at Skills Active for the rest of the year. By mid-2021, some of our back-of-house functions will start the transition to the WDC, and by mid-2022, workplace training delivery will begin the transition to the NZIST. The structural and operational details of these two organisations are still being decided, meaning that the implications for the avalanche industry, and indeed all outdoor recreation sectors, are not yet fully known. However, Skills Active has a central role in transition planning and we are working to make sure our industries are properly represented within these new organisations. - Nga Mihi
All the vocational training currently provided across polytechnics and ITOs will be bundled together, into a single national Institute of Skills and Technology (NZIST). The NZIST, through Centers of Vocational Excellence, will be responsible for delivering training and assessment to industry. The Tertiary Education Commission has confirmed that all industries currently within Skills Actives scope will be covered by a Creative, Cultural and Recreation Services WDC, for qualification oversight. However, we are still waiting on clarification of how training and assessment delivery for these industries will be arranged within the IST.
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For information on registering avalanche qualifications on NZRRP click the link below: https://nzrrp.activecv.co.nz/search_results_registra tion_criteria.php?filter_industry=6
Otago Polytechnic Professional Avalanche Programmes 2020 By Peter Bilous Avalanche Risk Management (ARM) L5 This course provides the first level of professional training available, enabling participants to work in all sectors of the avalanche industry. During this course, you will firstly gain a sound understanding of underpinning theory in your own time. You will then move into solidifying these concepts in a supportive group setting during the on-snow/classroom sessions. The course is 12-weeks long. Ten modules will be delivered via online study for ten weeks. This will include weekly live online study sessions to answer questions and refine concepts. During this ten-week period, you will also be asked to practice on-snow skills. You will then undertake one week of practical and assessment and have one week of reflection, during which you will evaluate your next steps and plan any re-assessment as required.
actively assisting in the management of avalanche hazard and risk including: ski areas, heli-ski operations, cat-skiing operations, snow-mobile operations, road contractors, alpine and other outdoor guiding and instruction operations, hunting, trekking, Department of Conservation, alpine search and rescue, and education providers. Are there any pre-requisites? Participants should be able to move safely and efficiently on all terrain and snow conditions. The 2nd intake is the only one that will cater for students not on skis or snowboard during the practical week. Students must also have a basic understanding of how to use a transceiver, shovel and probe. Evidence is required of this prior to attending the course. Please note: This qualification replaces our Avalanche Safety Stage 1 course.
All practical weeks are based in Wanaka and operate out of Treble Cone or Cardrona ski areas. There are 3 intakes: 1st intake starts w/ on-line study 28 April practical week 4-10 July (FULL w/ waiting list). 2nd intake starts w/ on-line study 8 June practical week 15-21 Aug (places available). 3rd intake starts w/ on-line study 14 July practical week 19-25 Sept (places available). On-line study can take place anywhere in the world. Weekly 1 hr live web sessions are recorded and available if students cannot make the session. (i.e. in a different time zone, working, etc). What can I do with this qualification? Graduates may be employed or work as volunteers under (direct or indirect) supervision, in a range of operations
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Avalanche Risk Management (ARM) L6 This programme are for those intending to assume supervisory roles in all sectors of the snow safety industry as: guides, ski field ski-patrollers, avalanche forecasters, Milford Road workers, Search and Rescue, and DOC workers. The online nature of this programme ensures that you can fit your study around other commitments as we have flexible start dates for the theory courses and applied snow studies. The field training and integrated practical assessment have fixed dates. Dates to begin online study are flexible, but there are certain completion requirements prior to attending both the: Field Training, 19-24 July. Integrated Practical Application, 2-8 September.
education in New Zealand. OP uses instructors current with their skills and regularly practicing in industry, usually in leading roles and often internationally. You’ll also get to attend the practical week in Wanaka, in the heart of the Southern Alps. How do I find out more information or enrol? Students may find out more about these programmes, download the Basic Transceiver Competence attestation and enrol at: https://www.op.ac.nz/study/physical-activity-andwellbeing/new-zealand-certificate-in-avalanche-riskmanagement-level-5/ https://www.op.ac.nz/study/physical-activity-andwellbeing/new-zealand-certificate-in-avalanche-riskmanagement-level-6
Otago Polytechnic Avalanche Risk Management (ARM) Covid-19 Update from 26 March 2020 ARM Level 5:
Are there any pre-requisites? Students must have completed the New Zealand Certificate in Avalanche Risk Management (Level 5) or equivalent and 100 days of using those skills, preferably in an operational environment. ARM L5 graduates are encouraged to begin logging their 100 days toward their ARM L6 programme as they begin using their ARM L5 skills, especially when they begin working. Why train with Otago Polytechnic? Otago Polytechnic has been delivering some form of this first level professional course since the early 80’s – nearly 40 years; by far the most expereinced provider of avalanche NZAD 62
We have 3 intakes of this programme, with the first, (fully subscribed, Intake 1), beginning April 28, 2020 with 10 weeks of on-line study. At this stage, it’s business as usual, regarding the on-line study. Students can expect to receive their 1st assignment via email a week before the course start date. It’s important that the email address provided when enrolled is one that you actively use and regularly check. It’s anybody’s guess as to whether the practical week can happen and then if so, how it will take place. It’s a dynamic environment that depends on government policy and ski field access. We will all need to be flexible. I would think the worst-case scenario for the programme is that the scheduled practical components are postponed until a later date. With some positive progress containing the virus, we may back in socialising mode by the 1st practical week in early July. Students can enrol on-line at: https://central.op.ac.nz/study/snowsports/new-zealandcertificate-in-avalanche-risk-management-level-5/ ARM Level 6: The 2 theory courses (Terrain & Snowpack and Decision Making & Operational Performance) and the required pre-
Field Training study are available now and an excellent objective during the lockdown period. You must enrol in these courses and can do so online at:
https://central.op.ac.nz/study/snowsports/new-zealandcertificate-in-avalanche-risk-management-level-6/ As per above, the government policy and ski field access at the time of the scheduled Field Training (3rd week in July) and the Integrated Practical Application (early Sept) will determine when and how we manage the practical components. At least these dates are pretty far in the future and hopefully some form of social gathering is safe to do then. Note: As of April, 2020, you may see correspondence from us at Otago Polytechnic (OP) re-branded as ‘The New Zealand Institute of Skills & Technology’ (NZIST). NZIST is the temporary name for a proposed vocational education provider in New Zealand. In February 2019, it became known that the country's sixteen Institutes of Technology and Polytechnics (ITPs) will merge to form the new organisation. That is scheduled to occur in April 2020.
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Slow Skinners
A Community-Minded Mentorship Initiative By Bob Miller This all started six years ago when several mountain bikers went for a ride with the Canterbury Mountain Bike Club (CMBC). At the ride we asked if there were any mid-week events scheduled and found out there were none. We decided that we were keen and started some. At that stage, these rides were not ‘official’ club rides because we were not ‘assessed’ as club ride leaders. We were slightly intimidated by the idea of trying to keep up with expert riders so we developed an approach to riding which evolved to become ‘SlowRiders’'. Six years on SlowRiders has progressed from one mountain bike ride per week to three rides every week. We cater to all different ability levels and include a series of progression rides to help encourage skill advancement, and we hold courses and introductions to other activities such as backcountry mountain bike riding. There are some nights that we have over thirty riders show up! Our #weride mantra means we ride in any conditions – we just alter the trails accordingly.
SlowSkinners getting every last cm of pow-pow. Helena Sodergren after a ski descent of Castle Hill and Foggy Peaks.
Helena Sodergren having a blast on easy terrain behind Tekapo.
The key to SlowRiders success can be found in the culture that has evolved: we leave the race mentality at home, and are prepared to laugh. We encourage others to have fun and be social! No one is left behind and there is always someone acting as 'Tail End Charlie' to help with technical issues or offer up a bit of encouragement. After any ride we head somewhere cheap and cheerful for a coffee, beer or dinner to keep the banter going and to scheme other adventures and missions. Practically speaking the SlowRiders philosophy is not just, '"The pace of the group needs to be the pace of the slowest NZAD 64
person." This method constantly makes slower people feel like they have to try and keep up, which in turn makes them more likely to fatigue and fall out of the group altogether. Instead we actively monitor our groups pace. We don'ttry to keep up with the rider in front but rather we keep someone on our back wheel. If someone slows or is struggling, the whole group will slow down and be happy to travel at the slower pace. This atmosphere makes everyone feel involved and connected and there is always an awesome group dynamic. The success of SlowRiders has now led us to ask the question: "How would this transfer to ski touring?" and so we have started formulating ideas and thoughts about what we are calling "SlowSkinners". This group, like SlowRiders will likely grow and change as we see how our ideas work and as we are exposed to new ones. For now, we see our SlowSkinners trips occurring on simple terrain, with low avalanche risk, generally in-bounds. We want to provide participants with the time and space needed to build their skills, experience and fitness before attempting to apply any knowledge they may gain from other more formal courses
into more challenging terrain. We can focus on "bedding in" skills and techniques in an environment where banter and encouragement are more important than getting in the most vertical or deepest pow. We are involved in the Canterbury Ski Touring Group on Facebook and see social media as one way that we can spread our ideas and messages. Other people and groups are welcome to get in touch with us. We are not guides or instructors, rather we  see ourselves as the supplement to more formal courses by providing relaxed opportunities to discuss gear, practice techniques, practice with avalanche rescue equipment, and negotiate terrain safely. We have no idea how this will work, but after the success of SlowRiders we are sure that SlowSkinners will help more people to develop their skills and gain experience safely all while gaining more stoke from this game we love to play.
You can see the SlowSkinners origins here! We are SlowRiders at heart. Helena Sodergren on the Mt Cheeseman Ski Field access road.
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TECHNOLOGY& SCIENCE
67 Simon Morris - Milford Road LiDAR Project
70 David Hill and Todd Redpath - Snow Data Or... 74 Jeff Deems - Do You Know What Your Map Knows?
Ground-based LiDAR Imaging on the Milford Road By Simon Morris The Milford Road (State Highway 94) is located in the southwest region of the South Island of New Zealand. It is New Zealand's only public highway with a significant avalanche problem. The highway extends from Gore in the east to Milford Sound (Piopiotahi) in the west and traverses Fiordland National Park, a UNESCO World Heritage Area. The operation of the highway between Te Anau and Milford Sound includes an avalanche mitigation programme, an rockfall response plan , management of the Homer Tunnel general maintenance and incident response along the highway. In response to these challenges the Milford Road Alliance was formed, a partnership between the NZ Transport Agency and Downer NZ. Avalanches can seriously affect the highway from June to December. The avalanche mitigation area covers approximately 30 km of the highway or 60 km² of terrain beginning at the Hollyford Road junction (91 km north of Te Anau), and ending at Milford Sound. When the glaciers retreated from Fiordland the terrain was left with near-vertical walls and large, steep snow basins at higher elevations creating a perfect environment for avalanches. The Upper Hollyford and the Cleddau Valleys are frequently swept by avalanche events that flatten vegetation and historically have created large treeless areas on the valley floor. Because the region has been deeply glaciated, avalanches originate in the hanging snowfields, and plunge to the valley floor below. The avalanche tracks are very steep (6090°) and have an abrupt change of slope angle at the valley floor. These plunging avalanche events can have a mass of up to 300,000 tons, can reach velocities of 290 km/h and have debris densities up to 775 kg/m³. The effect of these types of avalanche events upon the local landscape are significant and have created avalanche tarns, impact ejection fields and caused major vegetation scarring. The avalanche start zones above the Milford Road can receive in excess of 9000 mm of annual precipitation. Precipitation rates of over 30 mm per hour are expected three or four times a winter on average. Winter storms can last several days or even weeks and can deposit over 300 mm of precipitation in a single day. In order to diminish the avalanche hazard to personnel and visitors while maximizing the operational time of the highway, the avalanche programme needs to monitor the seasonal
snow-cover along the Milford Road in near real-time. The monitoring of the snowpack in avalanche terrain requires techniques that work independently of weather and avalanche conditions, that cannot be destroyed by avalanches and that provide near real-time information on snow layers, and loading and stripping events. Furthermore, when conditions become too hazardous to operate the highway, the avalanche program requires tools to effectively and promptly reopen. In 2018 the Milford Road Alliance purchased a Riegl VZ®-6000 ultra-long-distance terrestrial LiDAR laser scanner to monitor the seasonal snowpack in the alpine environment along the highway. Typically laser scanners use wavelengths that have a short range (100 m to 500 m) with high absorption rates over snow and ice. The Riegl VZ®-6000 employs a different laser scanning system allowing for faster surveys of up to 222,000 measurements per second at distances up to 6 km away with an accuracy down to 15 mm. This makes it especially suited for measuring snow and ice covered terrain. The Milford Road Alliance is actively investigating the design and construction of a permanent alpine scanning site, and an associated communications and data processing system for the autonomous scanning of approximately ten square kilometres of avalanche terrain along the Milford Road. This is the first time a terrestrial laser scanner would be set up for real-time monitoring of seasonal snowpack in an alpine environment. Initial key outcomes for this project include: 1. High spatial and temporal resolution with near real-time information on snow layers, including loading and stripping events. Emphasis will be placed upon the scanning of snow surfaces pre-storm and post-storm. This will allow for the detection of avalanche events, detection of spatial distribution within new snow amounts and for mapping avalanche mitigation results. 2. Detection of glide slab deformation and measurement of water outflow from avalanche start zones. Water outflow would be monitored through waterfall imaging. 3. Increase our knowledge of the spatial distribution of snow depth and variations in the seasonal snowpack as it relates to avalanche formation and character along the Milford Road.
Below are some images gathered with the Riegl VZ®-6000 laser scanner with associated explanations: NZAD 67
Image 1 - A Glide Fracture Within Avalanche Debris (2019).In this scan we determined the source of a large amount of new avalanche debris observed in the valley floor. The results of the scan revealed the new avalanche debris observed was from a large glide fracture from the slopes above. Over the winter a large pile of snow debris from other avalanche events had consistently built up on a rock shelf below. During a springtime rain-on-snow event a glide fracture formed approximately 70 m wide and up to 16 m deep creating a massive crownline. A second rain-on-snow event the following week saw the lower glide slabs release. This scan is taken from 3 km away at a resolution of 20 cm.
Image 2 - Monitoring of Glide Fractures (2019). In this scan we determined that we can monitor and estimate the size and potential hazard that this particular glide slab presents to the highway below. We used false colour to help emphasize the interpreted snow depths of the slab. This glide slab is approximately 70 m wide and ranged from 1.5 m to 1.9 m in depth. This scan is taken from 3 km away to a resolution of around 10 cm. NZAD 68
Add a little bit of body text Images 3 & 4 – Avalanche Debris (2019).In these two scans we mapped and calculated the mass of avalanche debris in the valley floor near the highway. In the first image (at left) we utilised true colours to assist in the location of the avalanche debris in the valley floor. In the second scan (at right) we focused on the avalanche debris at one of the impact ejection fields. The depth of the avalanche debris ranges from 2 m to 5 m (green colour) and up to 10 m depth (red colour) in places.
Images 5 & 6 – Seasonal Snowfall (2019).In these scans of Mt. Crosscut we see the difference between an April 2019 scan of a permanent snowfield and the surrounding uneven granite bedrock (above). In image 6 (below) we see a constructed seasonal snow depth map. At the beginning of the winter snow depths ranged from 2 m to 3 m (green colour). Towards the end of the winter a maximum of over 15 m was recorded and the deep crevasses of the permanent snowfield are no longer visible. These scans are taken from 4 km away to a resolution of around 20 cm.
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Snow Data or No Data – It’s Up to You By David Hill and Todd Redpath You don’t need to be a backcountry skier/rider or an alpinist to benefit from reliable information on the snowpack. Now, you probably are, if you are reading this, so think about it for a minute…what do you typically want to know? You might be looking for an avalanche forecast, which requires site-specific information on the vertical structure and stability of the snowpack. You might be looking for less-detailed information on coverage; how long of a hike will you have from trailhead to snowline, for example. Or, is the bergschrund at the base of the couloir you want to ski still filled in? Well, even if the frontcountry is more your style or (gasp!) you don’t even ski/ride, you still benefit from information about the snow. Snowpack plays a huge role in regional water resources in many areas and water planners need regional-scale information on snow (water equivalent) depth and distribution in order to make accurate estimates of seasonal water yields. Meeting the information needs of all of these different user groups is a challenge since they have different requirements in terms of spatial and temporal resolution. The skier about to drop into a chute is thinking about the snow ‘right here, right now,’ but the water planner is thinking about the snow in a watershed that is hundreds or thousands of square kilometers
in extent. Fortunately, there are a lot of sources of snow data, although they vary in degree of accuracy, coverage, and resolution. In-situ, or ‘on the ground’ have historically been the most common. These measurements include those made by personnel ‘on the move’ in the field (Figure 1) and also those at fixed, stations. An example of the former could be an avalanche forecaster, heli ski guide, or ski patroller who records a measurement (pit profile, snow depth, other) in a database. Some of these databases are global (for example, SnowPilot), while other information gathering programs are unique to a particular country (for example, Canada’s Mountain Information Network, or MIN). In New Zealand, the Mountain Safety Council manages InfoEx for use by professionals in the snow and avalanche community. Fixed, automated stations often measure snow depth with an ultrasonic sensor and snow-water-equivalent (SWE) with a snow pillow. The density, period-of-record, and management of these stations vary considerably from country to country. In the United States, as an example, the snow telemetry (SNOTEL) network is run by the National Resources Conservation (part of the federal government) and includes about 800 stations in 13 western states. Many of the stations
Figure 1: David Hill carrying a Federal sampler (snow tube) for measurements of snow density near Thompson Pass, Alaska. Photo: Ryan Crumley.
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have periods-of-record in excess of 40 years, and the stations provide daily or sub-daily information on snow and, typically, weather. In discussing the development of NIWA’s snow and ice network (SIN) in 2013, it was noted that if New Zealand were to achieve the same coverage of alpine climate stations as Switzerland, they would need observations at 280 sites. In 2013, the SIN comprised eight stations. While the situation has improved since then, with NIWA’s SIN now including 13 stations, it’s no secret that1 there is a lack of routine seasonal snow observations in New Zealand. Along with standard meteorological observations, all SIN stations measure snow depth, and several sites have snow pillows for determining snow density and SWE. More recent upgrades to key sites have focused on adding solid precipitation and snow albedo measurements. The scientific community operate additional sites at Broken River (University of Canterbury), the Brewster Glacier and the Pisa Range (both operated by the University of Otago). These stations have a research focus of improving our understanding of snow and ice processes and underpinning the development and implementation of snow and glacier models in New Zealand. While data from University research stations are not currently available to the public, efforts to facilitate this are ongoing, with the hope that additional data can assist MSC avalanche forecasts and decision making for backcountry travellers. Snow courses are another source of data, and one that blends the characteristics of the above examples. They are manual measurements, requiring personnel in the field, but they are done at fixed locations and typically at regular time intervals (say, once per month). A snow course is simply a linear transect (usually a few hundred meters) along which a number of measurements are made. In the United States, snow courses often have very long periods of record, going back to the 1920s or 1930s. Snow course measurements in New Zealand have a more sporadic and discontinuous history. Historically, much of the scientific knowledge around snow accumulation in New Zealand has come from glacier mass balance programs and targeted field campaigns in the central Southern Alps. While in-situ measurements are highly valued, given that they are ‘ground truth,’ they cannot give a complete picture of the distribution and evolution of the snowpack. Manual surveys are labor intensive and, as a result, are comparatively infrequent. Automated stations have high temporal resolution but, due to cost, are limited in number. An additional limitation is that automated stations are often in regions of gentle terrain and only modest elevation. This is because vehicular access is usually needed for installation and maintenance. From the perspective of avalanche forecasting, this is unfortunate since high-elevation, complex-terrain areas are chronically undersampled. 1 Hendrikx, J. and Harper, A. 2013: Development of a National Snow and Ice Monitoring Network for New Zealand, Journal of Hydrology (NZ), 52, p83-95.
Remote sensing campaigns are able to help address some of these limitations. A common implementation of this is airborne light detection and ranging (LIDAR). In the past, this has been done with airplanes, but LIDAR measurements from drone platforms are increasingly common. Structure-from-motion (photogrammetry), again from airplanes or drones, is another popular remote sensing technique. Successful drone-based snow depth mapping campaigns been carried out across the University of Otago’s study basin in the Pisa Range (Fig. 2). The advantages of these methods include very high spatial resolution and coverage. One disadvantage is that airborne LIDAR costs typically limit the frequency of these surveys. Some programs will conduct only one survey per year, typically at the day of peak SWE. More extensive programs such as the Airborne Snow Observatory, which is run by the National Aeronautics and Space Administration in the U.S., conduct weekly or monthly surveys throughout the snow season. Drones, while covering smaller areas, provide very highresolution data and offer flexibility in timing.
Figure 2: A Trimble UX-5 fixed wing drone, having just landed after a successful flight to map snow depth in the Pisa Range, Otago, New Zealand. Photo Credit: Todd Redpath
As a final note on remote sensing, satellite assets continue to improve and the ICESat-2 mission (NASA) has great potential for determining snow depths by comparing snow-on and snow-off surveys. In New Zealand, the costs and logistics of capturing LIDAR measurements over alpine areas are prohibitive, but satellites increasingly provide a valuable data source across the infrequently visited and even less often instrumented mountains of New Zealand. Since the year 2000, sensors that permit daily mapping of snow cover at moderate resolution have been operational and have been used to study seasonal snow in the Waitaki and Clutha catchments. Currently, the University of Otago is leading work to map snow depth from high resolution satellite imagery. The data sources described above help snow scientists, snow safety professionals, and recreationists better understand the current state of the snowpack and also long-term (decadal in NZAD 71
scale) trends in snowpack characteristics. There are still opportunities, however, for collecting and distributing highvalue data from locations and times that are not currently covered by the measurement programs above. In particular, the backcountry community represents an invaluable asset to snow science since backcountry travelers (1) go far, (2) go high, and (3) traverse areas of complex terrain. In other words, they go where the snow is, and where the measurement stations are not! The Community Snow Observations (CSO; @communitysnowobs) project began in 2017 in the USA when researchers from the University of Alaska, the University of Washington, and Oregon State University began to wonder about the value of crowd-sourced snow depth data from backcountry skiers, snowboarders, snowshoers, and snowmobilers. The specific science question was whether or not these data could markedly improve high-resolution physically based models of snowpack evolution and distribution. The idea of creating a large network of ‘citizen scientists’ is not a new one. In the context of weather and snow observations, the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) has observers distributed throughout the United States who measure rainfall, snowfall, and hail. However, the CoCoRaHS project is largely a ‘backyard observer’ type program and does not sample high alpine environments. In New Zealand, NIWA released a Citizen Science app in 2019 that allows for the submission of snow depth measurements. So far, this platform has been focused on capturing observations of low-level snow fall events. And, many avalanche centers have their own portals for collecting and distributing relevant data and observations. For example, in New Zealand, observations can (and should!) be submitted to the New Zealand Avalanche Advisory (NZAA) via a browser. .Submissions are geo-referenced manually by panning and zooming a web map and a number of fields (aspect, elevation, snow depth, etc.) can be input. Avalanche Canada has a similar approach, supported by a mobile app. The goals and needs of the CSO project differ from the efforts above. CSO is not in the business of avalanche forecasting; their efforts are focused on improving snowpack models. A critical requirement is that the data be accurately (GPS) geo-tagged in the field. In alpine environments, snow depths can change quickly over short distances, so it is essential to know precisely where the measurements come from. Also, CSO seeks global coverage and is not a local or regional program. Finally, CSO embraces open-source, open-data principles and distributes its data to any interested party freely online. Now, citizen science does have some challenges. The measurements are opportunistic and depend upon decisions made by the citizen scientists themselves. CSO can offer some suggestions and guidance, but ultimately must give control of the experimental plan to the citizen scientists themselves. Another challenge has to do with data quality control.
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Tutorials are provided but, in the end, we need to accept that measurements are coming from a diverse body of contributors with differing levels of experience with data collection. To maximize the success of the project, the CSO team decided that (1) measurements should require a minimum of equipment, (2) the measurements should be extremely fast and easy to make, and (3) the flow of data from citizen scientist to project team should be highly automated. To meet the first two criteria, the CSO team decided to focus solely on snow depth measurements, rather than SWE measurements. Backcountry users have their beacons, shovels, and probes with them at all times. Right? You didn’t leave them in the car, did you? Most probes are 2.5-3.0 m in length with centimeter markings, making for a perfect measurement tool! There are some nuances to making a good snow depth measurement, but it takes only a minute or two to assemble a probe, make a measurement, re-stow a probe, and be on your way (Figs. 3, 4).
Figure 3: Ryan Crumley uses an avalanche probe to measure snow depth near Tuckerman’s Ravine, New Hampshire. Photo Credit: Joe Klementovich.
Figure 4: David Hill measures snow depths in the Craigieburn Range, Canterbery New Zealand. Photo Credit: Kendra Sharp.
Figure 5: Comparisons of model-estimated SWE and SNOTEL-observed SWE for the cases of (left) no assimilation and (right) citizen scientist assimilation. Model study site is Thompson Pass, Alaska, USA.Figure
Are you stopping to shed a layer? Great, take a measurement. Ripping skins before a descent? Take a measurement. Taking a break to wait for your slow(er) partner? Take a measurement. Are you that slow(er) partner? You’re probably out of breath; take a break and take a measurement. To meet the final criterion, the CSO team has partnered with Mountain Hub and SnowPilot. Mountain Hub developed an outdoor oriented, community-fueled app in 2015. The app logs location, time, and snow depth (and other variables of interest), and automatically transmits these data to the CSO team. No cell service? It doesn’t matter. Your phone’s GPS knows where you are and your measurement will get uploaded when you get back in service. The CSO team has tutorials online that will get you going, whether you are an iOS or Android user. SnowPilot is a desktop program preferred by many snow professionals. It allows for information on the snowpack profile to be submitted, including the total depth. Again, these data are then made available to the CSO team. The CSO team assimilates the snow depth data into their model simulations of snow processes. Every time a measurement is made and submitted, the error between the model-estimated depth and the actual depth at the
measurement location is used to steer the model back towards the ground truth. Tests of this assimilation strategy have shown that the contributed snow depth measurements dramatically reduce model errors (Fig. 5). Participation in the CSO program since its beginning has been excellent, with about 2000 participants contributing in excess of 10,000 measurements around the globe (Fig. 6). Feedback from participants has been very positive, with many users noting that their understanding of snow processes improved by regularly sampling the snow and seeing how it varied and changed over time. So, since we all want information on the snowpack (right?), CSO hopes that all backcountry users will recognize that their measurements are incredibly valuable. Please regularly submit your observations to your local avalanche forecasting center (NZAA or other, depending on where you live) so that they can continue to provide the best possible advisories and help keep backcountry users safe. And, please submit simple snow depth measurements to CSO from out in the field so that their team can work towards improving near-real-time snow products that are distributed to the public. There is no crowd-sourcing without the crowd, and CSO hopes to see more and more citizen scientists out in the snow during the coming snow season.
Want to work in the Snow this Winter? Click here for 2020 Employment Opportunities! Figure 6: Scatter plot of CSO citizen scientist observations of snow depth. Close to ten thousand measurements have been obtained in the first two years of the project. NZAD 73
Do you know what your map knows? Understanding digital tools for better route planning and travel habits. By Jeff Deems This story first appeared in the December 2019 issue of The Avalanche Review (38.2). In recent years many low cost digital mapping tools have emerged, bringing data sets that used to be squarely in the domain of specialists with expensive software into widespread public use. It is now common for backcountry riders to plan routes in advance, with distance measures, slope angles, forest cover, land ownership, and other relevant data, or to navigate in real time and revisit or share completed tracks. In some cases, these tools are linked with guidebook information and/or crowdsourced route content. Use of these tools is regularly integrated into avalanche education courses.
interact with these tools, this factor likely occurs frequently without obvious consequence.
But, as with any tool, they have limitations â&#x20AC;&#x201C; and in this case the limitations are not obvious and may even be hidden by implied precision.Â
THE DIGITAL ELEVATION MODEL
Unfortunately, digital terrain information appears to have played a role in recent avalanche accidents by steering users into unintended exposure. Due to the nature of this digital terrain information, and the manner in which we tend to
In this context, it is worth asking a couple questions to explore the potential pitfalls and proper use of these interactive digital maps: Are we making accuracy assumptions when using digital mapping tools? Are there best practices which will help us use these tools more effectively?
All of the current route-planning apps have one thing in common: they exploit digital models of terrain. There are a number of ways to display and convey terrain elevation, and they have evolved over time from flat paper maps to modern digital data in concert with measurement
Figure 1: Three representations of the same terrain: a contour map, a Digital Elevation Model, and a shaded-relief image derived from the DEM. NZAD 74
methods and display technology. Older maps used artistic techniques like hachures to convey relief in a semiquantitative way, and were largely replaced by contour maps, which more accurately quantify elevation and relief, with each contour tracing a line of equal elevation. These days we are accustomed to interacting with digital elevation maps and shaded relief to convey elevation in a software environment that allows us to exploit multiple data sources at once (Figure 1). This digital source – the Digital Elevation Model or DEM – is the fundamental data set for terrain analysis. This data format is Digital – the information is stored electronically; it stores terrain Elevation information – the land surface height above some reference elevation like sea level; and most importantly, is a Model – an abstraction or representation of reality, in this case typically arranged in a regularly-spaced grid. The statistician George Box provided probably the most eloquent summary of the topic here when he famously stated: “All models are wrong, some are useful.” There is utility and power for us in knowing more about ways in which these models can be wrong, so that they can be most useful to us in managing avalanche danger. Not all terrain models are created equal. The method by which a specific DEM was created depends on its date of creation and what source data was available. Elevation source data can be collected from field surveys, airborne or satellite camera imagery, or active remote sensing techniques like radar or lidar. Until the advent of mapping tools in the 1980s and 90s, the predominant elevation resource in the United States was the 7.5’ quadrangle map series, produced by the US Geological Survey through analysis of overlapping aerial photographs. Using a device called a stereoplotter, a technician would manually trace lines of equal elevation – contour lines – to produce each paper quad map. Most DEMs available today through the US National Map are these same data – created by digitizing the paper 7.5’ quad maps, and interpolating the contour line elevations to a regular, 30-meter grid – one elevation value every 30 meters. These 30m data sets have since been reinterpolated to a seamless 10m data set, and this is the DEM source most widely available in the continental US. Beginning in the early 2000s, several space missions provided globally available elevation data. The ASTER sensor on NASA’s Aqua and Terra satellites produce 90m resolution elevation models from stereophotos, while the Shuttle Radar Topography Mission (SRTM) produced 90 and 30m DEMs using radar interferometry. Though they have been improved by recent reprocessing, these DEMs have specific shortcomings in forested or rough terrain and should be
treated with caution at fine scales. DEMs generated these days are commonly based on remotely sensed lidar data or on high-resolution satellite photos, either of which allow 1- or 2-meter resolution terrain data to be generated at high accuracies. Lidar has the additional advantage of being able to map under forest canopies, producing ‘point clouds’ of elevation measurements of the forest and the bare surface. These point clouds are then aggregated to a DEM, and provide an accurate reference against which to evaluate the more commonly available data sets. Because of this variety of elevation measurement technology, mapping techniques, and sensor resolution, DEM accuracy varies by location. Different techniques and measurements have varying ability to map surface elevation in complex terrain or under forests. Errors also result from the digitization and interpolation methods. Additionally, features that are smaller than the grid size can be missed (more on that in a moment). The end result is a complex and spatially variable pattern of elevation errors and data quality. These errors can present as a bias, as systematic errors, or as spatially correlated errors – separately or in combination. Importantly, it is not obvious to a digital map user which data source is in use, or what the DEM accuracy might be in a specific area. In most of the continental US, the most widely available DEM is the 10m NED DEM, digitized from pre-1979 topo maps, and while some specific areas have been mapped with lidar, even those lidar resolutions vary from 1 to 5 m depending on the technology used for the survey. High-res lidar coverage is increasing steadily due to USGS 3DEP and FEMA floodplain mapping programs, so the data availability is continuously evolving. Alaska typically has lowerresolution DEMs, with 30m SRTM DEMs being the current standard, though the USGS is currently building out a 5m radar DEM. Globally, the mix expands further, adding national mapping programs with similar technique, resolution, and accuracy variations as we have in the States. Slope Angle Maps When the concern is with navigating and route-planning in avalanche terrain, slope angle is the terrain feature of primary interest rather than simply elevation values. Slope angle is defined as the change in elevation (Rise) divided by the distance over which that change occurs (Run). Rise divided by Run and a little trigonometry gives us the slope angle, which is typically derived for each grid cell in a DEM data by considering the local neighborhood at each cell. Solving for the maximum elevation change within the 3x3 block of grid cells surrounding the target cell gives us a NZAD 75
magnitude and direction of slope for that cell – the magnitude being slope angle and the direction being slope aspect. At this point DEM errors and limitations start to come into play. Errors in the DEM and the ability of the DEM resolution to capture the terrain variations can combine to compound errors in slope angle. Thus there are two primary sources of error when producing slope angles in DEMs: elevation errors in the DEM, and impacts of DEM resolution. With resolution, we are concerned with the size of each grid cell compared to how rough the terrain is. If the terrain changes elevation substantially over, for example, 5 meters of distance, but our DEM can only capture values every 30 meters, then a lot can happen on the terrain between elevation measurements. The profiles in Figure 2 illustrate these resolution effects. If we calculate slopes between the grid cell centers (red lines) it is clear where slope angles are underestimated, and the peaks and valleys get clipped. Some of that detail can be estimated by doing a better interpolation (making curves instead of straight lines), but that is effectively an informed guess, with unquantified impacts on slope angle accuracy. A look at overall statistics of elevation and slope across a DEM at different grid resolutions shows that the average values for elevation and slope don’t change much with a coarser grid, but the max and min elevations get smoothed off. And most importantly, the maximum detectable slope angle decreases dramatically. THIS IS IMPORTANT – with coarser elevation models, our ability to detect and map steeper slopes goes away.
Figure 2: Schematic elevation profiles for 20, 10 and 3m DEM resolutions, with the gray bars representing the profile of grid cell elevations, and the black line representing the true terrain profile. As the DEM grid is coarsened, the ability to capture terrain variations and accurate slope angles decreases. (after Hengl and Evans, 2009)
The perspective views of two different DEMs and their respective slope angle maps in Figure 3 demonstrate the comparative level of detail and in the steepness of individual terrain features. It is clear that even with this relatively small resolution change from the 10 m USGS DEM to a 3 m LiDAR DEM, there is a dramatic difference in the ability to capture the slope steepness, as well as smaller terrain features. Imagine that we are using the 10 m data set to plan a route (dotted line). Ignoring for a moment whether it is a good idea to travel under all of the potential overhead hazard, the route itself attempts to exploit lower-angle ramps in the terrain to gain the ridge – at least according to the 10 m data. Plotting the same line on the higher-resolution map, suddenly the route is crossing a bunch of short, steep, slopes that are not evident in the coarser data set. In some terrain, features like this might be easily avoidable by the alert route finder, but in other may result in unwitting commitment to avalanche hazard exposure. Even though a higher resolution model tends to be a more accurate representation of the terrain, we can still use a NZAD 76
Figure 3: Perspective hillshade views of 10m (top Left) and 3m (top right) DEM's, and slope maps derived from each in the lower panels. The different levels of terrain detail captured is readily apparent, and the slope angles calculated from the finer-scale grid are substantially steeper.
coarser data set as a guide and tool for planning and navigating. The key is understanding how and where elevation model information can be incomplete: in complex or forested terrain, on features close in size or smaller than the DEM resolution, and in steeper areas. This description sounds a lot like terrain traps, and also describes small features that can be trigger points, or areas that may look like islands of safety but are not in actuality. By adding safety margin to accommodate these uncertainties, we can use the valuable information present in the DEM without inadvertently increasing exposure.
On the positive side, digital terrain data and planning tools provide a wealth of information to exploit. Regardless of the specific slope angle accuracy, the presence of overhead hazard can be anticipated. Often, an indication of the relative terrain steepness can be extremely useful – focusing on mellower or steeper rather than the specific slope angle. Mapping apps can add photos showing forest density or rock outcrops, which can be just as important for travel as the terrain itself. While micro-routefinding requires constant field awareness rather than app-dependence, macro-scale planning is greatly aided by digital tools.
Converging on Best Practices
As with stability assessment, we can plan our route, then continually re-assess and be nimble enough to alter that plan when what we observe on the ground doesn’t match our expectations. While looking for signs of instability, we should simultaneously be evaluating terrain features with a keen eye and our trusty inclinometer, recognizing in the same uncertainty context that the expected snow structure and the expected slope angles may be different than the forecast or our digital tools indicate. Our minds will tend to focus on what the visual tool shows, not what it doesn’t show or what it implies. Active questioning is imperative to overcome this trap – does that narrow line on the map really distinguish safety from danger, or do we need more information?
To summarize, the primary ways in which digital terrain models can fail us: Small terrain features are often not captured by DEM Errors in DEM could omit, create, or mis-represent the size and shape of terrain features, due to forest cover, steeper slopes, & complex terrain Digital slope angle is likely low-biased In addition to these issues, the digital tools in common use struggle to communicate the level of uncertainty in the underlying data – partly due to the nature of digital tools in general (not specifically the data they use) – in that there is an implied or assumed accuracy in the digital format that can be misleading. The fixed scale of paper maps allows an intuitive sense of distance and the size of terrain features, however the rapid scale changes possible with digital maps foster a dependence on the tool, and provide no corresponding visual cue that the accuracy may not support use of the data at that scale. Further, our decision-making process must allow for compounding & interacting errors. For example, in addition to terrain model and slope angle errors, there is uncertainty in GPS positioning and therefore in our knowledge of our location in the terrain. Encountering these uncertainties when fatigued, in white-out conditions, or with a less-skilled or injured partner can pose serious problems. Putting this information into practice, use of digital terrain tools can fit right into our existing uncertainty paradigm in evaluating avalanche danger and traveling safely. Knowing how digital data are produced can inform their use & weak points. In our route planning & decision-making processes, we can treat terrain analysis in the same manner that wetreat stability assessment – acknowledging inherent, leading us to incorporate wider margin into our route planning process. For example, narrow, lower-angle gaps in the slope angle shading may be enticing, but those features may not exist, and they may be connected to surrounding, steeper slopes.
By getting our heads out of our phones and actively looking for ways the terrain is different from what our digital planning suggested, we can reduce our likelihood of being surprised by the terrain. Rules of Thumb are rarely appropriate in the avalanche world, but here’s one that might keep us out of trouble: It’s probably steeper than the slope map says. Resources and Further Reading: US Geological Survey DEM product: availability:https://www.usgs.gov/core-sciencesystems/ngp/3dep/3dep-product-availability-maps NASA Shuttle Radar Topography: Missionhttps://www2.jpl.nasa.gov/srtm/ ASTER Global DEM: https://asterweb.jpl.nasa.gov/gdem.asp Hengl and Evans, 2009. Mathematical and Digital Models of the Land Surface, in Developments in Soil Science, Volume 33, DOI: 10.1016/S0166-2481(08)00002-0. McCollister, C., and K.W. Birkeland, 2008. “Using GIS for avalanche work” The Avalanche Review. 24-4Scott, D., 2009. “Avalanche mapping: GIS for avalanche studies and snow science” The Avalanche Review 27-3
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