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Snow storm in the Sierra Nevada on last day of summer turns deadly

Summer snow

TRUCKEE, Calif. -- An early season storm turned deadly Thursday as a slick roadway on a highway in California triggered a chain reaction crash involving 16 vehicles and at least one fatality.

The California Highway Patrol said the crash happened about 11:05 a.m. between Cisco Grove and Emigrant Gap, CBS San Francisco reports.

At the time of the crash, authorities said, the roadway was covered with a layer of hail. The National Weather Service has issued a winter weather advisory for the Lake Tahoe area on Thursday, the last full day of summer.

Forecasters said an unseasonably cool weather system could drop 3 to 6 inches of snow along Interstate 80 above 7,000 feet. Up to 8 inches was possible over higher peaks of the Sierra Nevada.

Snow falls in the Sierra Nevada mountains on the last day of summer, Thursday, Sept. 21, 2017. CBS San Francisco

"Since late September is an unusually early time for this amount of snow we have decided to issue a winter weather advisory above 7000 feet with main concern near Donner pass," the weather service said.

Cameras captured snow at Sierra-At-Tahoe resort and in the South Lake Tahoe area.

The early season flurries come a little over two months since the last of the Sierra resorts shut down their runs for the 2016-2017 season.

During last year's historic snowfall, Squaw Valley received 728 inches of snowfall and stayed open through July 4.

According to new data released by NASA in April, the snowpack levels in the Sierra were larger than the last four years combined.

The Sierra snowpack is a major source of water for the San Francisco Bay Area and California's Central Valley. NASA's Airborne Snow Observatory (ASO) measured the Tuolumne Basin snowpack on April 1.

The critical annual measurement of snow revealed the snowpack was at 1.2 million acre-feet. According to NASA, that is enough snow to fill the Rose Bowl in Pasadena, California, nearly 1,600 times.

The 2017 California snowpack is close to the largest on the record, NASA said. Those records consists of decades' worth of snow measurements made at ground level.

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