Funding for this research was provided by the Sulo and Aileen Maki Endowment at the Desert Research Institute. We thank Anne Nolin and Gene Mar for use of the snow disappearance date product derived as part of the NASA funded project entitled, New Metrics for Snow in a Warming Climate: Indicators for the National Climate Assessment, and Nathaniel Brodie who assisted in the fieldwork. In addition, we thank Roger Kreidberg and Jay Arnone who reviewed early versions of the paper.
Forest management -- Environmental aspects, Forest fires -- West (U.S.)
Forest fires are increasing across the American West due to climate warming and fire suppression. Accelerated snow melt occurs in burned forests due to increased light transmission through the canopy and decreased snow albedo from deposition of light-absorbing impurities. Using satellite observations, we document up to an annual 9% growth in western forests burned since 1984, and 5 day earlier snow disappearance persisting for >10 years following fire. Here, we show that black carbon and burned woody debris darkens the snowpack and lowers snow albedo for 15 winters following fire, using measurements of snow collected from seven forested sites that burned between 2002 and 2016. We estimate a 372 to 443% increase in solar energy absorbed by snowpacks occurred beneath charred forests over the past two decades, with enhanced post-fire radiative forcing in 2018 causing earlier melt and snow disappearance in > 11% of forests in the western seasonal snow zone.
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Gleason, K. E., McConnell, J. R., Arienzo, M. M., Chellman, N., & Calvin, W. M. (2019). Four-fold increase in solar forcing on snow in western US burned forests since 1999. Nature communications, 10(1), 2026.