Continued Below-Average Year for California Snowpack
The California wet season got off to a quick start, but then came to a screeching halt.
The Department of Water Resources (DWR) conducted the third manual snow survey of 2020 on February 27 at Phillips Station near Lake Tahoe. The manual survey recorded 29 inches of snow depth and a snow water equivalent (SWE) of 11.5 inches, which is 47% of the March average for this location.
“This past February, there actually wasn’t any recorded measurable precip in the northern Sierra on our 8 station index,” said Sean de Guzman, chief of DWR’s Snow Surveys and Water Supply Forecasting Section. “And that’s actually never happened before in its history since 1921.”
To monitor the health of the Sierra snowpack, officials take monthly observations to determine the snow water equivalent or SWE. The SWE measures the amount of water contained within the snowpack, which is a crucial measurement for forecasting runoff.
“The snowpack is like a reservoir and during the spring months into early summer, we see that snowmelt come into our reservoirs to add additional storage,” said Molly White, chief of DWR’S State Water Project, Water Operations Office.
Current readings statewide put the SWE just below 50% of average, with 2020 on pace to be a below normal year. This puts the pressure on March and April to catch up as 27 million people and 750,000 acres of farmland rely on California’s melting snow.
According to the DWR, the state’s largest six reservoirs currently hold between 92% (Oroville) and 132% (Melones) of their historical averages for this date. Lake Shasta, California’s largest surface reservoir, is 107% of its historical average and sits at 78% of capacity. DWR conducts five media-oriented snow surveys at Phillips Station each winter in January, February, March, April and, if necessary, May. On average, the snowpack supplies about 30% of California’s water needs as it melts in the spring and early summer.