Snowstorm Dumps 12+ Inches In 24 Hours Over Parts Of The Sierra

SAN FRANCISCO — It's beginning to look a lot like winter in the mountains, thanks to a healthy dose of fresh snow, with more on the way. As rain showers graced the Bay Area, a cold front dumped more than a foot of snow over parts of the Sierra, and a winter weather advisory was expected to remain in place at higher elevations, including in the mountain passes, until late in the evening.

Overnight snowfall had already prompted some chain restrictions Thursday morning on Donner Pass.

"Snowfall will increase again over the mountains, with snow levels remaining around 4,000 - 4,500 feet," the National Weather Service's Sacramento wrote Thursday. "A Winter Weather Advisory continues through 10 p.m. PST tonight for the mountains of eastern Shasta County, western Plumas County/Lassen National Park, and the west slopes of the Northern Sierra Nevada, including Interstate 80 and Highway 50."

• Related: Meteorological Winter Is Here: Latest Forecasts For The Bay Area

Forecasters said preliminary reports showed at least a foot of new snow at Donner Peak, Bear Valley, and Sierra at Tahoe by Thursday morning, with 15 inches at Palisades Tahoe and 14 inches at Sugar Bowl.

At UC Berkeley's Central Sierra Snow Lab, which sits at 6,894 feet on Donner Pass, researchers said they doubled their seasonal snowfall in 24 hours, logging 11 inches of snow, with another 2 to 4 inches expected in the afternoon.

The first significant snowstorm of the season could be a sign of things to come, as forecasters predict a strong El Niño pattern will remain in place through the winter and into the spring, which is typically associated with more active winters in California.

In the near term, forecasters see a drier and warmer trend emerging in the mountains from Friday and lasting until at least the middle of next week. For the Bay Area, the weather will shift from rain to a sunnier trend Friday, which should hang on for the rest of the forecast period.

The nights, however, will take a chillier turn. The National Weather Service has issued a freeze warning for the North Bay, and patchy frost could impact the rest of the Bay Area Friday and Saturday mornings.