Sierra snowpack could drop significantly by end of century

• Researchers found that we could see on average a 79 percent drop in peak Sierra Nevada snowpack water volume by 2100.
• Peak snow melt could be as much as one month earlier, increasing the lag time between when water is available and when it is most in demand.
• “We basically get 50 percent of our annual precipitation in five to 15 days, or one to two weeks. Our water demand is highest during the summer months when we don’t get a lot of precipitation, so we really rely on mountain snowpack as a stopgap for our water supply.”

DOE/Lawrence Berkeley National Laboratory Read ScienceDaily coverage here

A future warmer world will almost certainly feature a decline in fresh water from the Sierra Nevada mountain snowpack. Now a new study that analyzed the headwater regions of California’s 10 major reservoirs, representing nearly half of the state’s surface storage, found they could see on average a 79 percent drop in peak snowpack water volume by 2100.

…the study found that peak timing, which has historically been April 1, could move up by as much as four weeks, meaning snow will melt earlier, thus increasing the time lag between when water is available and when it is most in demand.

…Mountain snowpack is a critical source of water for California, and much of it comes in a very narrow window. “Our precipitation is really intermittent and extremes-driven,” Rhoades said. “We basically get 50 percent of our annual precipitation in five to 15 days, or one to two weeks. Our water demand is highest during the summer months when we don’t get a lot of precipitation, so we really rely on mountain snowpack as a stopgap for our water supply.”…

Alan M. Rhoades, Andrew D. Jones, Paul A. Ullrich. The Changing Character of the California Sierra Nevada as a Natural Reservoir. Geophysical Research Letters, 2018; DOI: 10.1029/2018GL080308