California Snowpack: Trends, Variability, and Impacts

Keywords: Snowpack, California, Climate Change
Abstract Type: Poster Abstract

Abstract

Winter precipitation accumulating as snowpack in the high elevations of the Sierra Nevada mountain range is a critical source of spring and summer water supply in California. The seasonal development of this snowpack is observed with automated daily sensors (snow pillows) distributed through the high elevations as well as monthly manual measurements at snow courses. Timing and amount of runoff from this snowpack is observed at stream gages in the watersheds downstream. Natural mechanisms of climate variability such as the El Nino-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) produce variations in this water supply at various time scales, while ongoing climate change in the western United States is likely to affect the amount (water equivalent) of the snowpack as well as the timing of peak snowpack and the onset of the spring melt. Increasing temperatures, shifts from snowfall to rainfall, rising elevation of the snowline, and changing variability in the frequency and magnitude of storm events complicate the water supply picture. The focus of this project is the ongoing variability in the form, magnitude and timing of winter precipitation and runoff, with an emphasis on the spatial variabilities of socio-economic vulnerability to drought and downstream disruptions in this water supply across the state.