Aug 8, 2016

Testing the recent snow drought as an analog for climate warming sensitivity of Cascades snowpacks

Matthew G Cooper, Anne W Nolin, Mohammad Safeeq
Environmental Research Letters
  • States that record low snowpack conditions were observed at Snow Telemetry stations in the Cascades Mountains, USA during the winters of 2014 and 2015
  • Tests the hypothesis that these winters are analogs for the temperature sensitivity of Cascades snowpacks
  • States that in the Oregon Cascades, the 2014 and 2015 winter air temperature anomalies were approximately +2 °C and +4 °C above the climatological mean
  • Uses a spatially distributed snowpack energy balance model to simulate the sensitivity of multiple snowpack metrics to a +2 °C and +4 °C warming and compares modeled sensitivities to observed values during 2014 and 2015
  • Finds that for each +1 °C warming, modeled basin-mean peak snow water equivalent (SWE) declined by 22%–30%, the date of peak SWE (DPS) advanced by 13 days, the duration of snow cover (DSC) shortened by 31–34 days, and the snow disappearance date (SDD) advanced by 22–25 days
  • Results show that the hypothesis is borne out only by the peak SWE observations
  • Results indicate that rather than just temperature, the magnitude and phasing of winter precipitation events, such as large, late spring snowfall, controlled the DPS, SDD, and DSC