Water, sediment supply reqs—post-wildfire debris flows in western U.S.

We sometimes fall back on an implicit model that post-wildfire debris flows are only triggered once a certain level of saturation or rainfall is reached, and that the sediment supply is soon exhausted and future flows are unlikely until it recharges. In this research, we explore a revised model, that there is usually ample water in the system both before and after the flow, that antecedent moisture only plays a small role, and that sediment supply is not a limiting factor (this last one seems to be the case right now in Glenwood Canyon). We will also look at quantitative changes in debris flow abundance and impacts as a result of changing climate.

Santi P (2021). Water and sediment supply requirements for post-wildfire debris flows in the western United States. USGS Landslide Hazards Program Seminar Series, 15 September 2021.