Time-lapse videos: Storm blankets California’s Sierra Nevada in white

With an atmospheric river bringing rain and snow to California this week, the state’s mountains began to change from summer brown to winter white.

Mammoth Mountain expected around 2 feet of snow by Tuesday night. The UC Berkeley Central Sierra Snow Lab forecast up to a foot at its location near Lake Tahoe, lab director Andrew Schwartz said.

The snow arrived at a moment when snowpack levels were down to nearly zero across the Sierra Nevada range after melting off over the summer. In addition, the National Oceanic and Atmospheric Administration declared last week that La Niña conditions had arrived. The ocean phenomenon is a driving factor behind drought.

But experts told The Times that the early storm set the state off on the right foot.

By Tuesday afternoon, many of the mountain cameras across the Golden State maintained by UC San Diego’s ALERTCalifornia camera network showed whiteout conditions.

The video below shows Frazier Mountain towering over Interstate 5 near Gorman on Tuesday.

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In the video, snow blankets the mountaintop whose peak is around 8,000 feet, some 2,000 feet below that of Mt. Baldy.

The next video shows Bald Mountain in the southern Sierra, within Sequoia National Forest.

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Its slightly higher peak — around 9,400 feet — saw significant snow on Tuesday, with more expected in the evening.

The storm — classified as a weak, or Level 1, atmospheric river — brought enough moisture to Southern California’s drought-stricken landscape to delay fire season for weeks, if not months.

“In a way this is like a Goldilocks atmospheric river,” said Marty Ralph, director of the Center for Western Weather and Water Extremes at UC San Diego’s Scripps Institution of Oceanography. “It’s sort of just right to be mostly beneficial at this stage of the year.”

Times staff writers Hannah Fry, Clara Harter and Alex Wigglesworth contributed to this report.