Estimated Loss of Snowpack Storage in the Eastern Sierra Nevada with Climate Warming

The average loss of snowpack storage from a warmer versus current climate in the Owens River basin of the Eastern Sierra Nevada was estimated using 9 years of gridded, daily fractional snow-covered-area data from satellite, plus ground-based reconstructions of daily potential snowmelt from snow pillow sites in the basin. This basin provides water supply for the City of Los Angeles, and snowpack is the main surface storage in the system. The snowpack occurs mainly above 1,500-m elevation and increases in depth up to the Sierra crest above 3,900 m. Snowmelt or seasonal snowpack storage currently averages about $0.42+0.15\mathrm{m}$ per year in the Owens River basin. Considering only the direct effect of temperature changes on snow, this amount is projected to decrease about 0.036 m for each 1°C of warming, equivalent to a 50% loss of snowmelt with a 6°C warming. For a current average snowmelt of about 1,460 $\pm 480\times 106{\mathrm{m}}^3$ for the Owens headwaters, this represents a loss of snowpack storage of about $120\times 106{\mathrm{m}}^3$ per °C of warming. Snowcover depletion is projected to occur about 8–12 days earlier for each 1°C of warming.