California's snowpack sees solid rebound. Here's how much is saved in the Sierra

SACRAMENTO, Calif. — California’s snowpack made a solid rebound ahead of the summer months, thanks to a string of cold and wet storms that pounded the Sierra Nevada in February and March. But even with the late-season boost, the statewide reserves remain smaller than they were a year ago.

Amid a steady stream of snowflakes at Phillips Station, the state Department of Water Resources conducted its last manual survey of the season Friday near Sierra-at-Tahoe in El Dorado County, a few days early to avoid more winter storms forecast for the week. This annual measurement marks the traditional peak of the Sierra Nevada snowpack — the mountain snow bank that feeds much of California’s water supply.

Statewide, the average snow-water equivalent stood at 23.5 inches, or 90% of the April 1 average, based on measurements reported Friday morning across 103 electronic snow sensor sites.

The survey at Phillips Station recorded a snow depth of 39.5 inches and a snow-water content of 17 inches — about 70% of the April 1 average. That’s up from 34 inches a month ago and 24 inches at the start of the year, said Andy Reising, who manages the Department of Water Resources’ Snow Surveys and Water Supply Forecasting unit.

“This will be the third year in a row that the snowpack conditions at the start of April are near or above the average,” he told reporters after the manual survey. “And ... there’s more in the forecast.”

Still, Reising said, the increasing occurrence of extreme and unpredictable weather events, like floods and droughts, could strike at any moment and erase those benefits.

“It’s the California way,” he said.

While this year’s snowpack is healthier than what water managers feared during January’s dry spell, it still trails last year’s April 1 levels. On the same date in 2024, the statewide snowpack averaged 27.4 inches, or 106% of the April 1 average. Each Sierra zone — north, central and south — reported deeper snow and higher water content a year ago.

But a 90% snowpack, Reising was “pretty good” considering the quiet December and January, which had worried water officials.

“We’ve had back in 2015, 5% of the annual snowpack on April 1. So we’re at 90% ... I’m feeling generally positive, especially (since) earlier in the season there were some indications that maybe this would be a drier year.”

The late-season parade of storms — none of which were blockbusters but were consistent at higher elevations — “opened up in both February and March and allowed us to accumulate more during this year,” he said.

Snowpack conditions vary by region. The northern Sierra — home to the state’s most productive watersheds — now sits at 109% of its April 1 average, with 29.2 inches of snow water. The central Sierra measured 22.9 inches, or 83%, while the southern Sierra, which started the year especially dry, reached 18 inches, or 81%.

“While it’s positive news today, we know that our luck could run out and we could fall into a drought any time,” Reising said.

Even so, those figures represent a sharp recovery from early January, when statewide snowpack measured just 2.7 inches — only 10% of the April 1 average and 28% of normal for that date. In the southern Sierra, snow water content was a mere 1.5 inches on Jan. 2.

The March storms didn’t just improve snowpack — they also boosted reservoir levels statewide.

The state’s largest reservoir, Lake Oroville, is now at 87% of capacity and 121% of its historical average for this time of year. Earlier this week, DWR raised the State Water Project allocation forecast to 40% of requested supplies, up from 35% last month, citing improved conditions.

San Luis Reservoir — shared by the state and federal water projects — is at 89% of capacity and 104% of its historical average. DWR has nearly filled its portion of that key water bank, officials said.

The State Water Project serves 27 million Californians and 750,000 acres of farmland. The new allocation also reflects successful reservoir operations during this year’s variable weather.

Reising emphasized that runoff from the Sierra remains uncertain and will depend heavily on spring temperatures and weather conditions in the coming weeks. Water deliveries could still change depending on how much snow actually melts into rivers and reservoirs.

As the snow begins to melt, the state will need to balance water supply, environmental needs and flood protection. In the Sacramento-San Joaquin Delta, water exports are expected to slow in April and May to protect endangered fish species. Releases from Oroville may also be adjusted to support water quality.

“These constraints reinforce the need for California to invest in additional water supply infrastructure,” DWR said in a statement. The agency noted that the proposed Delta Conveyance Project, had it been built, could have captured an estimated 750,000 acre-feet of water this winter — enough to raise the State Water Project allocation by another 20%.

The U.S. Bureau of Reclamation, meanwhile, under pressure from President Donald Trump to increase water output across the Central Valley Project, announced Thursday that it had upped its allocation five percentage points to 40% as well. Federal water irrigates most of the San Joaquin Valley and has double the capacity of the state.

Federal reservoirs were also in strong shape. Lake Shasta, California’s largest surface reservoir, is at 87% of capacity and 111% of its historical average. Other major reservoirs — including the Army Corps of Engineers’ Folsom Lake — were near or above 100% historical averages heading into the dry season. As of Friday, Folsom Lake sat at 128% of its historical average and 79% of capacity with anticipated runoff starting to ramp up.

Only Castaic Reservoir in Southern California was lagging behind at 79% of capacity, 94% of its historical average.

Environmental concerns will also shape spring operations. In the Delta, pumping operations are expected to slow in April and May to protect endangered fish species. Depending on conditions, DWR may release water from Oroville and other reservoirs to maintain water quality and ecosystem flows.

Officials say this year highlights the value of additional water infrastructure. Had the proposed Delta Conveyance Project been in place, DWR estimates it could have captured more than 750,000 acre-feet of water this winter — enough to boost the State Water Project allocation by another 20%.

The final water allocation for 2025 will be announced later this spring, once snowmelt and runoff conditions become clearer.

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