California's Largest Reservoir Is Almost Completely Full

Lake Shasta is nearly full, according to a chart depicting current conditions at California's major reservoirs.

After years of drought, several reservoirs in California reached concerningly low water levels in the summer of 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.

This year, Lake Shasta's water levels began significantly improving in January after a series of atmospheric rivers—which bring saturated air from the tropics—supplemented the lake. It has jumped 47 feet since the start of the year. As of Monday, its levels were at 96 percent capacity, making it 117 percent of its historical average.

Lake Shasta's water level is at 1,059.95 feet, only 7 feet below full pool. It also is nearing last year's peak of 1,063 feet, which occurred in late May.

It's possible the lake will continue rising throughout the snow melt period. The snowpack in the Sierra Nevada, which provides 30 percent of the state's water supply, begins to melt in April.

The most recent update from the California Department of Water Resources (DWS) was issued on Monday. Data revealed that statewide, the snowpack is 112 percent of average. The Sierra Nevada snowpack in the northern mountains is 125 percent of average. The central Sierra Nevada snowpack stands at 108 percent, and the southern Sierra Nevada's is at 106.

"Here is a look at the latest data from CDEC/DWR, showing a slightly above normal snowpack to date for the Sierra Nevada, as of today (April 15th)," the National Weather Service (NWS) office in Sacramento posted on X, formerly Twitter, with a graphic depicting snowpack levels.

A California Department of Water Resources spokesperson told Newsweek that the snowpack typically peaks around April 1.

"It is extremely rare for the snowpack to continue building past the middle of April and with the current weather outlooks, it is likely the snowpack for the Northern Sierra peaked this season around April 1," the spokesperson said.

Snowpack levels have improved significantly since the start of the winter. At the beginning of January, they were only 28 percent of normal. However, several atmospheric rivers supplemented the levels—including one storm that brought 10 feet of snow to parts of the Sierra Nevada mountains in March.

Both Lake Shasta and Lake Oroville—the state's second largest reservoir, which is at 90 percent of its capacity—are fed by the northern Sierra Nevada snowmelt, meaning that the levels at both lakes could continue to rise throughout the spring.

Both lakes have already been rising at such a rate that water officials have voluntarily released water from the reservoirs since they were too high.

Last year, water officials were able to store all the water in Lake Shasta.

Update 4/16/24, 1:57 p.m. ET: This article was updated with comment from the California Department of Water Resources.