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Dryad

Dynamically downscaled 15-minute U.S. West Coast precipitation (Part 3/3)

Michaelis, Allison1; Gensini, Vittorio1

Published Feb 23, 2024 on Dryad. https://doi.org/10.5061/dryad.nvx0k6dzm

Data files

Abstract

High-intensity, short-duration rainfall can trigger deadly and destructive debris flows in steep and severely burned terrain. Although we can identify rainfall thresholds to delineate the conditions for which postfire debris flows typically initiate, the spatial and temporal resolution of climate models has hampered our ability to characterize future trends in hazard potential. Here, we use novel dynamically downscaled, convection-permitting simulations of 15-minute rainfall to evaluate rainfall threshold exceedance for late 21st-century climate scenarios in the American Southwest. We observe significant increases in the frequency and magnitude of exceedance across the Southwest, including regions dominated by cool- and warm-season rainfall. We also observe greater increases in the frequency of exceedance in some regions where communities are less accustomed to contending with postfire debris flows, compared to areas where the hazard is well known. Our findings support proactive measures to save lives, mitigate damage, and increase resiliency to postfire debris flows under a changing climate. This is part 3 of the full dataset containing 15-minute rainfall over the late-century period (2085–2100) following the RCP8.5 emissions scenario.