California snowpack below average — what does this mean for water supplies?

Despite some heavy rainstorms and squalls of snow in recent months, the Sierra Nevada snowpack today stands at 90% of average, according to state officials.

This year’s measurements mark a sharp uptick from a year ago, when the statewide average lagged at 38%. Still, it’s nothing like the record-smashing snowpack of 2023, which measured more than twice the historical average.

Snow levels at this time of year are considered especially important, since they help water managers determine how much water will be available through the dry season, which typically begins around May.

Sierra Nevada snowpack supplies about a third of the state’s water on average.

As snow fell this morning, a Department of Water Resources survey team measured several spots on the snowy meadow at Phillips Station, a few miles south of Lake Tahoe. The average snow depth was 39.5 inches, with a water content of 17 inches — numbers representing 70% of the April 1 average for that location.

“We hope to add a few more inches before the year is out,” said Andy Reising, manager of the Snow Surveys and Water Supply Forecasting Unit. He noted that storms forecast to cross the Sierra next week could add another layer of snow.

Reising said the erratic winter weather patterns of the past six months “are a good reminder that the next flood or drought could come at any time.”

“We know future years won’t all unfold like this one has, and in addition we know that floods and droughts can happen at any time,” Reising said. “It is the California way of life to expect that.”

Throughout the state’s main mountain range, snowpack averaged from more than 250 sites ranged from above average to considerably below. In the northern Sierra Nevada and southern Cascade peaks, it stands at 108% of the historical April 1 average, but in the central and southern Sierra, it’s just 83% and 81%.

The data reflects a sharp regional discrepancy this winter, with wet conditions prevailing in the northern half of the state and drought across Southern California. Reising noted that Southern California has experienced roughly 50% of its average annual rainfall.

Sierra Nevada snow provides cold runoff that feeds rivers and reservoirs and helps support fish habitat all summer.

“As we near the end of the wet season, our focus shifts to snowpack runoff and whether temperatures allow for a slow melt so we can capture as much of that runoff as possible,” said Department of Water Resources Director Karla Nemeth.

The north-to-south disparity in the state’s precipitation this year “affects how much water the State Water Project will be able to deliver,” she said.

“It’s great news that our state’s snowpack has recovered from several weeks of extremely dry conditions in the heart of our winter storm season,” Nemeth said. “However, it’s not a wet year across the entire Sierra Nevada.”

State officials earlier this week announced that deliveries to water users would be increased this year from an earlier allocation. As of March 25, water users who depend on the State Water Project receive 40% of requested supplies.

A final allocation will be issued in May or June and could result in another increase, according to the department.

The State Water Contractors, which receives and distributes the water to farms and urban areas, mostly in Southern California, issued a statement on March 25 noting a “mismatch in hydrology and exports” from the Delta.

General Manager Jennifer Pierre urged state officials “to continue to pursue modernized infrastructure to further develop scientific rationale to refine regulatory requirements and ramp up adaptive management.”

Reservoir levels statewide are well above average. In Southern California, in spite of a relatively dry winter, most reservoirs are nearly full. In Northern California, Lake Shasta, the state’s largest reservoir, is 111% of its average capacity for this date. Lake Oroville, the largest reservoir of the State Water Project, is at 120%.

Together, these two reservoirs now contain about 7 million acre-feet of water. While that’s almost enough water to supply all of the state’s residents for about two years, most of it is diverted to farms.

The U.S. Bureau of Reclamation, which manages the Central Valley Project, has also announced an increase in the 2025 allocation of water supplies.

President Donald Trump repeatedly tried to blame water issues and the Los Angeles fires on the Newsom administration’s management of Delta water supplies. Though corrected repeatedly by media and outspoken officials, he ordered the release of water from two federal reservoirs in late January. San Joaquin Valley farmers and others said the releases wasted water because they came at a time when their crops didn’t need irrigation. That water also doesn’t reach Los Angeles.

California’s ski resorts report mixed results this year. Mammoth Mountain has reported 248 inches of snow this season, considerably less than the ample amounts that fell during the past two winters but more than the 168 inches in the drought-plagued winter of 2014-15.