Powerful storms over the past week dumped the most snow on the Sierra Nevada in a few days than any time in more than 40 years.

Over the five days from Feb. 16 to Feb. 20, a total of 111 inches of new snow fell at the University of California’s Central Sierra Snow Lab near Donner Summit off Interstate 80. That deluge — more than 9 feet in 120 hours — is the most snow to accumulate in any five-day period since April 1982, when 118 inches fell, according to the lab, and the third-most since its records began in 1946. December 1970 ranks second, when 113 inches fell.

The huge storms came after five weeks of dry weather through January, and have boosted the state’s water fortunes.

On Jan. 6, the Sierra Nevada statewide snow pack — which provides about 30% of California’s water supply — was 93% of its historical average. By Feb. 11, it had fallen to 55%. On Monday, it was up to 73% with another four to six weeks of winter remaining.

The all-or-nothing winter also contributed to the tragic avalanche that killed nine backcountry skiers near Castle Peak, a few miles from Donner Summit, on Feb. 17. Experts said that the warm weather in January hardened the existing snow, covering it with feet of soft powder, and increasing avalanche risk.

All of the snow over the past week, which helped struggling ski resorts around Lake Tahoe increase their totals, will slowly melt in late spring and summer, running down rivers, with some being captured in reservoirs. After three wet winters in a row, the state’s reservoirs were already more full than normal heading into this winter, and nearly all are expected to fill to the top by June.

A car is covered with snow near Castle Peak in Nevada County near Truckee, Calif., on Friday, Feb. 20, 2026. Nine backcountry skiers were killed in an avalanche near Castle Peak on Feb. 17, 2026; six survived. (Ray Chavez/Bay Area News Group)