Publications

Graber, AP; Thomas, MA; Kean, JW (2023). How Long Do Runoff-Generated Debris-Flow Hazards Persist After Wildfire?. GEOPHYSICAL RESEARCH LETTERS, 50(19), e2023GL105101.

Abstract
Runoff-generated debris flows are a potentially destructive and deadly response to wildfire until sufficient vegetation and soil-hydraulic recovery have reduced susceptibility to the hazard. Elevated debris-flow susceptibility may persist for several years, but the controls on the timespan of the susceptible period are poorly understood. To evaluate the connection between vegetation recovery and debris-flow occurrence, we calculated recovery for 25 fires in the western United States using satellite-derived leaf area index (LAI) and compared recovery estimates to the timing of 536 debris flows from the same fires. We found that the majority (>98%) of flows occurred when LAI was less than 2/3 of typical prefire values. Our results show that total vegetation recovery is not necessary to inhibit runoff-generated flows in a wide variety of regions in the western United States. Satellite-derived vegetation data show promise for estimating the timespan of debris-flow susceptibility.

DOI:
10.1029/2023GL105101

ISSN:
1944-8007