Organization of the 2019 National THIRA

This document contains two main sections and five appendices. The first section National THIRA Overview provides a conceptual overview ofthe National THIRA and how it fits into FEMA’s vision for a broader national assessment. Informed by this conceptual overview, the second section 2019 National THIRA: Methodology and Outputs describes the full approach FEMA took to complete the 2019 National THIRA. This section briefly outlines the steps FEMA has taken to identify the Nation’s realistic worst-case scenarios and their impacts, and how FEMA established capability targets that provide specific capabilities required to manage those impacts. This section also includes a brief description of the outcomes of the 2019 National THIRA.

The five appendicesoffersupplementalinformationthat supportsthe 2019 National THIRA, elaborating on specific data and processes. Appendix A: Limitations and Future Research describes caveats and limits to the use of the 2019 National THIRA, including data constraints encountered throughout development. This appendix also discusses how future National THIRAs will address those challenges. Appendix B: Scenario Context Descriptions includes the context descriptions that FEMA developed for each of the final scenarios,3 including the Plausible Concurrent Operations Appendix C: Standardized Impacts defines the 29 standardized impacts, which are the metrics that FEMA used to estimate the impacts resulting from the threat and hazard scenarios Appendix D: Scenario Chronology offers visualizations to illustrate the timelines of the incidents included in the Plausible Concurrent Operations, as well as the scenarios used for the 2019 National THIRA. 4 Appendix E: Standardized Targets presents the 22 standardized targets for the Cross-Cutting, Response, and Recovery core capabilities without impacts or timeframe metrics.

3 FEMA removed context descriptions and data for two scenarios that FEMA deemed too sensitive for inclusion in the public version of this document.

4 FEMA removed two scenarios from the chronology that FEMA deemed too sensitive for inclusion in the public version of this document.