Diving deep
(underwater)
into Missoula history MISSOULIAN STAFF One of the interesting aspects of moving to a new community is learning its history, including the ancient geologic kind. To me, and to many others, one of the more startling facts about Missoula is that it sits at the bottom of what was once a giant Ice Age lake. Not just any lake, either, but a destructive force. Catastrophic floods from Glacial Lake Missoula tore across what is now Idaho, Washington and Oregon more than 12,000 years ago, transforming the landscape. I’m a native of eastern Washington and went to high school in Coulee Dam. I grew up wondering with amazement at the sheer elemental forces that carved the grand coulee, the surrounding scablands and the bed of the Columbia River. Dry Falls was scoured by a waterfall seven times the size of Niagara. The floodwaters ran with a force equal to 60 times that of the present-day Amazon River. Car-sized boulders
The Missoula valley seen from Blue Mountain.
Tom Bauer, Missoulian
The most obvious clues are the ancient
death in 2015. It’s written for non-scientists,
shorelines etched high up on Mount Sentinel
and asks and answers many questions an
(the one with the “M”) and Mount Jumbo (the
inquiring mind would like to know.
one with the “L”). They are especially visible
Both guides are available at local bookstores.
when the snow starts melting in late winter. There are also the roadcuts just east of the
Learn more!
Interstate 90 bridge across the Clark Fork
The Montana Natural History Center at 120
at Ninemile, west of Missoula, where you
Hickory Street in Missoula has a permanent
can see layers of sediments deposited by the
exhibit, including a video overview, dedicated
The lake was formed by the Cordilleran Ice
floods. And the giant ripples in the valley
to the glacial lake. It’s open by appointment
Sheet, which formed an ice dam more than
floor of Camas Prairie, west of Flathead Lake
Wednesdays and Sundays due to the pandemic,
2,000 feet tall, blocking the Clark Fork River
northwest of Missoula.
but the staff hopes to reopen in full sometime
embedded in ice floated 500 miles toward the Pacific Ocean and are still visible, dumped in the oddest of places.
downstream of what is now Missoula. Over
Hyndman co-authored a book with Robert
this summer. Call 406-327-0405 or go to
the course of a millennia the lake — the size of
C. Thomas called “Roadside Geology of
montananaturalist.org for hours and more
lakes Erie and Ontario combined, also covering
Montana,” the second edition of which was
information.
many of the surrounding valleys of western
published last year. It’s packed with photos,
There’s also a local group called the Glacial
Montana — periodically broke through the ice
maps and graphics of how landscapes across
Lake Missoula chapter of the Ice Age Floods
dam, filling and emptying more than 50 times.
the state were formed, making it a useful travel
Institute. They host occasional “Cabin Fever”
Visual evidence
accessory for your vehicle.
lectures on the floods — Hyndman was a recent
Don Hyndman, professor emeritus of
Another good resource is the book “Glacial
speaker. They also organize annual field trips
geosciences at the University of Montana,
Lake Missoula and its Humongous Floods,” by
open to the public. They have a Facebook page
says the visual evidence is all around us, if you
former UM geology professor David Alt, who
(@GlacialLakeMissoula) and a new, improved
know where to look.
studied the subject from the 1960s until his
website at glaciallakemissoula.org. N
Missoula.com/newcomers
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