Dynamically downscaled 15-minute U.S. West Coast precipitation (Part 1/3)

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 1 of the
full dataset containing 15-minute rainfall over the historical period
(1990–2005).