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Midwinter dry spells amplify post-fire snowpack decline

February 3, 2023

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

Publication Year 2023
Title Midwinter dry spells amplify post-fire snowpack decline
DOI 10.1029/2022GL101235
Authors Benjamin J. Hatchett, Arielle L. Koshkin, Kristen Guirguis, Karl Rittger, Anne W. Nolin, Anne Heggli, Alan M. Rhoades, Amy E. East, Erica R. Siirila-Woodburn, W. Tyler Brandt, Alexander Gershunov, Kayden Haleakala
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70240268
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center