How California Reservoirs’ Water Levels Will Change After Winter Storm

Southern California has faced an exceptionally dry winter thus far, contributing to the wildfires currently raging in the state, but an ongoing winter storm will alleviate some of that struggle, including a slight benefit to reservoirs in the area.

Why It Matters

As of Monday afternoon, multiple winter weather-related alerts and warnings from local National Weather Service (NWS) offices remained in place across southern and central California, including winter weather advisories and winter storm warnings.

People were advised against travel in some areas as snow continues to fall.

What To Know

Most of the advisories, including the winter weather advisory issued by the NWS Hanford office for the Sierra Nevada mountains from Yosemite National Park to the Grapevine, will expire by Monday afternoon.

The snowfall, estimated to be around 4 to 7 inches, will add to the below-average snowpack, which is only 40 to 60 percent of average as of this date, NWS meteorologist Stephen McCoy told Newsweek.

Water levels at most of the reservoirs in the area begin to steadily climb during the spring months when snowpack in the mountain melts. However, McCoy said the current winter storm could have “contributed a little bit” to reservoirs in the area.

However, he said the impact will be more notable when snow begins to melt in the spring.

As of Monday, data from the California Department of Water Resources (DWR) show that despite the abnormally dry start to winter for Southern California, most of the state’s major reservoirs are performing above average for this time of year.

Newsweek reached out to the DWR by email on Monday for comment.

Most of California’s reservoirs saw a significant recovery in 2023 and 2024 after experiencing years of drought. However, concerns about the state of the reservoirs have been on the rise, particularly in parts of the state that are experiencing below-average precipitation during the state’s wet season.

Although the rain and snow might be a respite for the dry weather in Southern California after the series of wildfires, the burned land is at risk of hazards from the storms.

What People Are Saying

California Governor’s Office of Emergency Services said in a post on X (formerly Twitter): “Rain is welcomed relief after wildfires, however it can cause secondary disasters. Normally, rain soaks into the soil and vegetation, but burn scars make it repel rain just like pavement…causing mudslides and debrief flows. Stay vigilant and listen to local authorities.”

A winter storm warning issued for Southern California said: “Roads, and especially bridges and overpasses, will likely become slick and hazardous. Plan on slippery road conditions.”

What Happens Next

McCoy told Newsweek that for the next five days, the Hanford, California, forecast region isn’t expecting “too much precipitation,” meaning the region’s snowpack will likely remain below normal for now.

Another winter storm system could bring more snow to the area this weekend, though the amounts aren’t looking to be very high.