Characterizing changes in postfire debris-flow hazard as burned areas recover

Geosphere
By: , and 

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Abstract

Emergency assessments of postfire debris-flow hazards that are performed by the U.S. Geological Survey (USGS) provide estimates of debris-flow likelihood and rainfall triggering conditions that are used for evaluating and managing runoff-generated debris-flow hazards in recently burned areas throughout the western United States. Although the immediate postfire period, within roughly one year after fire, is typically the most susceptible to runoff-generated debris flows, the hazard evolves in time and space as the burned area recovers. The recovery trajectory a given burned area will take depends on local climate and weather and can be difficult to predict. Some burned areas recover quickly, whereas others experience debris flows for multiple years after fire. As a result, extending our ability to update debris-flow likelihood estimates and rainfall thresholds based on observed recovery of the burned area would be beneficial. We present a method for multi-year runoff-generated debris-flow hazard assessment that leverages the USGS “M1” debris-flow likelihood model and integrates updated, satellite-derived, normalized burn ratio data to estimate vegetation recovery. We predict recovery-aware rainfall thresholds and validate them against a multi-year debris-flow hazard prediction and could be adapted for use with other debris-flow models that incorporate burn severity data.

Suggested Citation

Graber, A.P., Thomas, M.A., Kean, J.W., King, J., and Kostelnik, J., 2026, Characterizing changes in postfire debris-flow hazard as burned areas recover: Geosphere, 22 p., https://doi.org/10.1130/GES02936.1.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Characterizing changes in postfire debris-flow hazard as burned areas recover
Series title Geosphere
DOI 10.1130/GES02936.1
Edition Online First
Publication Date April 16, 2026
Year Published 2026
Language English
Publisher Geological Society of America
Contributing office(s) Geologic Hazards Science Center - Landslides / Earthquake Geology
Description 22 p.
Country United States
State Arizona, California, Colorado, New Mexico, Washington
Other Geospatial western United States
Additional publication details