A Lasting Snowfall in Sierra Nevada Boosting California's Water Reserves

Significant snowfall in the Sierra Nevada over the coming days might be the season’s final major snow event, highlighting a notable recovery for the snowpack, which plays a key role in bolstering California’s water reserves throughout the year.

The wintry weather descended on the Sierra Nevada, the mountain range straddling the California-Nevada border, starting Sunday. Predictions indicate substantial accumulations by Tuesday, with elevations over 4,000 feet potentially receiving one to four feet of snow. Meanwhile, peaks exceeding 8,000 feet might see snow reaching five feet.

“It’s coming in really heavy right now,” reported Andrew Schwartz, director of the Central Sierra Snow Lab at the University of California, Berkeley, on Monday morning. “I think it’s one of the snowiest periods we’ve experienced all season.”

This snowfall is part of a vast storm system that impacted the entire West Coast on Monday, anticipated to bring scattered rains ranging from Seattle to Los Angeles. Southern California is also expected to receive some precipitation, although less than the northern regions, according to Dr. Schwartz.

The main headline, however, is the snow.

The Weather Service described the storm system as “robust” and winter-like in the Sierra Nevada, prompting several winter storm warnings that advised against mountain travel through Tuesday. During intense snow periods, drivers will likely need to use tire chains on major roads, including Interstates 80 and 50, which are crucial routes to and from the Tahoe Basin.

Additionally, the Klamath Mountains and the Cascade Range in Oregon and California are predicted to experience significant snowfall.

Such substantial snowfall spells good news for the Sierra snowpack, which is vital for water supply in both California and Nevada. As the snowpack melts over the spring and summer months, it replenishes reservoirs and aids fish habitats in rivers.

Earlier in the year, concerns arose over the snowpack due to arid conditions, but it has since rebounded to near-normal levels—recording 89 percent of the average as of last Friday—thanks to other late-season storms. A healthy snowpack in the Northern Sierra is helping to offset shortages in Southern California, which has seen below-average precipitation this season.

Following a persistent drought in California, the last two winters finished with normal or above-normal snowpack levels. A repeat of this trend for a third consecutive year would be uncommon, but not impossible, with the last occurrence in the consecutive winters of 1998 to 2000, and prior to that from 1978 to 1980.

“This storm may deliver,” said Dr. Schwartz, who closely monitors snowfall at the lab located on Donner Pass off Interstate 80 in the Central Sierra. “I think we might wind up just slightly below average, but this storm will be a significant boost.”

As the season progresses, the snowpack’s size is crucial, marking its peak before it begins to melt. Water managers rely on end-of-season data to estimate water availability for the coming winter. During last week’s annual ceremonial snowpack survey, they ventured into the snow at Phillips Station near Lake Tahoe on Highway 50 to gather measurements.