Midwinter Dry Spells Amplify Post?Fire Snowpack Decline

Increasing wildfire and declining snowpacks in mountain regions threaten water availability. We combine satellite-based fire detections with snow seasonality classifications to examine activity California's seasonal ephemeral zones. find a nearly tenfold increase during 2020–2021 versus 2001–2019. Accumulation season broadband albedo declined 25%–71% at two burned sites (2021 2022) according in-situ data relative un-burned conditions, greater declines associated increased burn severity. By enhancing snowpack susceptibility melt, both decreased canopy drove midwinter melt multi-week dry spell 2022. Despite similar meteorological conditions December–February 2013 2022–linked persistent high pressure weather regimes–minimal occurred 2013. Post-fire differences are confirmed satellite measurements. With growing geographical overlap between snow, our findings suggest is increasingly vulnerable the compounding effects of spells wildfire.