Debris-flow hazard maps and geospatial data are now available on the Post Wildfire Debris Flow Hazard Assessment Dashboard.
Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The U.S.G.S. conducts post-fire debris-flow hazard assessments for select fires in the Western U.S. We use geospatial data related to basin morphometry, burn severity, soil properties, and rainfall characteristics to estimate the probability and volume of debris flows that may occur in response to a design storm. Visit the U.S.G.S. postfire debris-flow project page for more information about postfire debris-flow hazards.
Hazard maps depict the likelihood of debris-flow generation and estimates of flow magnitude in locations where debris flows initiate. The models do not predict downstream impacts, potential debris-flow runout paths, and the areal extent of debris-flow or flood inundation.
For information on what to do if you live in a recently-burned area where debris flows are possible, and there is a rainstorm - before, during, and after, download the
National Weather Service Debris-Flow Survival Guide