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Midwinter dry spells amplify post-fire snowpack decline
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  • Benjamin J Hatchett,
  • Arielle Koshkin,
  • Kristen Guirguis,
  • Rittger Karl,
  • Anne Nolin,
  • Heggli Anne,
  • Alan M. Rhoades,
  • Amy E East,
  • Erica R. Siirila-Woodburn,
  • W. Tyler Brandt,
  • Alexander Gershunov,
  • Kayden Haleakala
Benjamin J Hatchett
Desert Research Institute

Corresponding Author:[email protected]

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Arielle Koshkin
Colorado School of Mines
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Kristen Guirguis
Scripps Institution of Oceanography, Univ. California, San Diego
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Rittger Karl
Institute of Arctic and Alpine Research, University of Colorado, Boulder
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Anne Nolin
University of Nevada, Reno
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Heggli Anne
Desert Research Institute
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Alan M. Rhoades
Lawrence Berkeley National Laboratory
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Amy E East
United States Geological Survey
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Erica R. Siirila-Woodburn
Lawrence Berkeley National Laboratory (DOE)
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W. Tyler Brandt
Scripps Institution of Oceanography
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Alexander Gershunov
Scripps Institution of Oceanography, Univ. California, San Diego
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Kayden Haleakala
University of California Los Angeles
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Abstract

Increasing wildfire and declining snowpacks in mountain regions threaten water availability. We combine satellite-based fire detection with snow seasonality classifications to examine fire activity in California’s seasonal and ephemeral snow areas. We find a nearly tenfold increase in fire activity during 2020 and 2021 compared to 2001-2019 as measured by satellite data. Accumulation season snow albedo declined 17-77% in two burned sites as measured by in-situ data relative to un-burned conditions, with greater declines associated with increased soil burn severity. By enhancing snowpack susceptibility to melt, decreased snow albedo drove mid-winter melt during a multi-week midwinter 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. Our findings suggest larger areas of California’s snowpack will be increasingly impacted by the compounding effects of dry spells and wildfire.