Forecast, monitor, adapt: A multi-agency strategy to protect people from postfire debris flows

GSA Today
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Abstract

In 2020, a wildfire burned across Glenwood Canyon in Colorado, USA. A history of postfire debris flows in the region and a hazard assessment for the burn area indicated that potentially life-threatening debris flows could be triggered by rainfall within months of a wildfire. As a result, four government agencies evaluated strategies to help mitigate hazards, including the loss of human life, that may be associated with debris-flow events. After the fire, 26 large debris flows occurred in the summer of 2021 and three sediment-laden flows occurred in the summer of 2023, but there were no major injuries or fatalities reported. We found that integrating hazard assessment/ forecasting, monitoring, and adaptation scenarios was a successful strategy for reducing postfire debris-flow risks to human life (including injuries and fatalities). Weather forecasts and estimates of debris-flow triggering rainfall thresholds, likelihood, and volume were used to anticipate the timing, location, and magnitude of debris-flow events. Rainfall monitoring and detailed recordkeeping of storms that triggered debris flows were used to validate and update debris-flow warning thresholds that varied with time following the wildfire. Although the governmental agencies working in this burn area had distinct and differing agency mandates, they were able to integrate information to reduce the risk of debris-flow events to human life.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Forecast, monitor, adapt: A multi-agency strategy to protect people from postfire debris flows
Series title GSA Today
DOI 10.1130/GSATG611A.1
Volume 35
Issue 8
Publication Date August 01, 2025
Year Published 2025
Language English
Publisher Geological Society of America
Contributing office(s) Geologic Hazards Science Center - Landslides / Earthquake Geology
Description 6 p.
First page 16
Last page 21
Country United States
State Colorado
Other Geospatial Glenwood Canyon
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