Post-Wildfire Debris-Flow Runout Hazard Assessment (PWFDF-R) Collection (updated 20260423)

Wildfire can substantially alter the hydrologic response of watersheds to rainfall, and debris-flow activity is among the most destructive consequences of these events. To assist federal, state, and local agencies in planning for postfire hazards, the U.S. Geological Survey conducts debris-flow hazard runout assessments. This collection contains the results of those assessments conducted since 2024. Each child item holds the results for a given version of a hazard assessment.

These results map the likelihood and potential volume of debris flows in the source catchments and the downstream runout for a series of design rainstorms. Assessment results are generally representative of the conditions immediately after the fire. The files, data fields, and metadata included in each assessment strictly conform to the Post-Wildfire Debris-Flow Runout (PWFDF-R) Data Specification. This specification extends the Post-Wildfire Debris-Flow (PWFDF) Data Specification (https://doi.org/10.5066/P14EWYME) to include information about runout. You can find archived versions of all current and historical versions of the PWFDF-R data specification here: https://doi.org/10.5066/P15CKL9J.

Collected hazard assessments are produced via the Landslide Hazards Program's ursa codebase. The source code for the codebase is available here: https://doi.org/10.5066/P15CKL9J.