The Sierra Nevada Regional Report includes climate science, impacts, and adaptation information for Alpine, Amador, Calaveras, El Dorado, east Fresno, central Kern, Lassen, east Madera, Mariposa, Modoc, west Mono, Nevada, west Placer, Plumas, Sierra, east Tulare, and Tuolumne counties.
The Sierra Nevada region encompasses the Sierra Nevada mountain range in eastern California, a natural wonder and biodiversity hotspot. Elevation rises from the western foothills around 1,600 feet to Mount Whitney at 14,505 feet, the highest point in the contiguous United States. The Sierra Nevada is the ancestral and contemporary homeland of many Tribes and Tribal communities, including but not limited to the Mono, Miwuk, Paiute, Washoe, Yokuts, and Tübatulabal peoples. About 1.2 million people call the region home across rural towns and small cities, including over 70 Native American tribes.
The Sierra Nevada region experiences cool, wet winters and warm, dry summers, with considerable variability across the region. Forests, shrublands, and grasslands make up around 90% of the region’s landscape. Compared to the western side, the eastern side is drier and more rugged due to the rain shadow effect and steeper slopes. Land uses include national parks, national forests, designated wilderness and monuments, timber production, livestock grazing, hydropower generation, recreation, and limited agriculture. The region provides important ecosystem services, including carbon storage in forests and meadows, winter recreation, hydropower generation, and habitat for aquatic and terrestrial ecosystems.
The Sierra Nevada plays a critical role in California’s water system. It provides an estimated 26 million acre-feet of streamflow annually to the Central Valley and functions as the state’s “natural reservoir,” with snowpack storing approximately 15 million acre-feet of water. Snowmelt sustains rivers, reservoirs, aquatic life, and water systems during the prolonged summer dry period.
Under rising temperatures due to climate change, these water sources are projected to decline severely and shift in seasonal timing, creating water management challenges. Meanwhile, wildfires present the most acute threat to communities across the region. Multiple efforts are underway to help the region adapt to the new realities of a warmer and drier future.
Sierra Nevada Regional Report
Coordinating Lead Author
Safeeq Khan, UC Merced