Snow Surveys

Department of Water Resources January Snow Survey 2020

Department of Water Resources staff at the January 2020 snow survey. DWR/2020

Established in 1929 by the California Legislature, the California Cooperative Snow Surveys (CCSS) program is a partnership of more than 50 state, federal, and private agencies. The cooperating agencies not only share a pool of expert staff but share in funding the program, which collects, analyzes and disseminates snow data from more than 265 snow courses and 130 snow sensors located throughout the Sierra Nevada and Shasta-Trinity mountains.


California is the only western state to perform this function on its own. In the other western states, snow surveys are done by the federally funded Natural Resources Conservation Service, which began its program in the mid-1930s. Both programs are similar, and there is a high degree of cooperation between the two entities.

DWR is the lead agency in coordinating the CCSS program, which includes:

  • Maintaining snow surveying and sampling equipment
  • Training for our partner agencies 
  • Course measurement schedules and data collection
  • Fiscal and staff resource needs for the various partners within the program.

The CCSS program also forecasts seasonal and water year runoff for the major snow bearing watersheds in California. Water supply forecasts in the Bulletin 120: Water Conditions in California series are vital for planning and managing the state's water resource systems to benefit all Californians.


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