How California's Largest Reservoir Could Change After Next Storm

More wet weather is on its way to Northern California, and the approaching storm could benefit Lake Shasta's water levels.

After years of drought, several reservoirs in California reached concerningly low water levels in summer 2022. However, an abnormally wet winter last year alleviated much of the state's drought and replenished the lakes. A similarly wet winter has brought a deluge of rain to the state this year, and several California cities have already received their annual allotment of rainfall. Lake Shasta, the state's largest reservoir, neared capacity last year but began declining in the summer.

The lake has been steadily increasing since the start of the month, adding 8 feet to its water levels since March 1. The lake dropped 8 feet in late February after water officials voluntarily released some from the lake through Shasta Dam because the lake's levels were too high for February.

As of Thursday morning, the lake was at 1,046.32 feet, a little less than 21 feet below full pool and 20 feet higher than this time last year. The lake has jumped more than 30 feet since the start of the year after a slew of atmospheric rivers brought plenty of precipitation to the Golden State. More rain is on the way, although it's not expected to be as severe as the atmospheric rivers that pummeled California earlier this year.

"Here comes the rain again," the National Weather Service (NWS) office in Sacramento posted to X, formerly Twitter, on Thursday afternoon, with a map of the storm's forecast. "Light to moderate rain is expected this Friday through Sunday, with heaviest rain occurring in the foothills and northern Sacramento Valley. Roads will be slick, so leave a little extra time for any travel."

The map showed that up to 1.5 inches of rain was expected in Redding, California, which is near Lake Shasta. The highest amounts of precipitation from the approaching storm were expected in Blue Canyon, Sonora and Yosemite Valley, where 2 to 3 inches of precipitation was forecast.

Prior to beginning flood operations on January 31 because of the lake's swollen state, officials had not conducted flood operations there since 2019, Don Bader, U.S. Bureau of Reclamation area manager in Northern California, previously told Newsweek. Typically, flood operations occur at Lake Shasta once every five years.

Newsweek reached out to the U.S. Bureau of Reclamation on Thursday via email for comment.

Lake Shasta's water levels could continue to rise significantly through the spring as the snow melts.

California's snowpack levels started off below average this year but greatly improved following heavy snow in February. The state relies on snowmelt through the spring to supplement as much as a third of its water supply.