FIRE, FLOOD, AND MUD: ASSESSING POSTFIRE DEBRIS-FLOW HAZARDS THROUGHOUT THE ROCKY MOUNTAIN REGION

The Rocky Mountain Region has a history of damaging debris flows after wildfire, and it is facing expanded postfire risk due to increased wildfire activity and development in susceptible areas. After a wildfire, emergency managers need rapid answers to the questions: Where in the burn area are debris flows likely? How much rain will it take to trigger a debris flow? And how big will that debris flow be? Using examples of recent postfire events in Colorado and New Mexico, we describe how the U.S. Geological Survey and research partners have worked to improve the answers to those questions over the last twenty-five years. We also describe current work to improve debris-flow hazard assessments with new tools to answer the questions: Where will debris flows travel? How long it will take the burn area to recover? And what are the risks from future fires?