Snowmelt from the Sierra Nevada Mountains provides roughly 75 percent of California’s agricultural water, and 60 percent of Southern California’s water resources. Warm winters can cause snow droughts in the Sierra Nevada, both by nudging precipitation in the direction of rainfall rather than snowfall, and by melting snow sooner. A new study by researchers at the University of California, Irvine, uses historical records and modeling to understand how the Sierra Nevada snowpack may respond to rising temperatures. Based on the new study, this figure shows how the snowpack could fare in the Sierra Nevada with a 1°C (1.8°F) increase in average winter air temperature.