A sprawling winter storm system continued to wreak havoc on Monday in the Western United States, where an 81-mile stretch of an interstate in the Sierra Nevada remained closed by blinding snow while temperatures plunged to record lows in Seattle.
The lingering system rendered several major highways and state roads in Northern California impassable, with public safety agencies posting video warnings of the extreme conditions.
The closed roads included Interstate 80, which was shut down from Placer County near Sacramento to the Nevada state line, and Highway 50 in Sacramento Valley and the Lake Tahoe Basin, according to Caltrans.
A winter storm warning remained in effect for most of the region until 9 p.m. local time on Monday, the National Weather Service said, adding that some areas could get another two feet of snow.
“The impacts on the roads are quite severe, and travel, in some cases, will be outright impossible,” Andrew Orrison, a meteorologist in College Park, Md., at the Weather Prediction Center of the Weather Service, said on Monday.
On State Route 89, an avalanche closed the road from Tahoe City, Calif., to near Squaw Valley, the site of the Winter Olympics in 1960, the California Highway Patrol said on Twitter on Monday.
The storm, which began over the holiday weekend, shattered records for snowfall and low temperatures across the West.
At a research station operated by the Central Sierra Snow Lab of the University of California, Berkeley, the snowfall for December surpassed 193 inches as of Monday morning — a record, researchers said. The previous record of 179 inches was set in 1970, said the lab, which is at an elevation of 6,894 feet.
“P.S. Sorry for the late update today!” the lab said on Twitter. “That snow was deep and hard to get through to do the measurement. It took us 40 minutes to get from the front door of the lab to where the measurement is completed 50 yards away!”
In a region that has been beleaguered by wildfires and drought, the record-setting snowfall could have its benefits. “It’s really good news for the water supply out there,” Mr. Orrison said.
In California, there were more than 115,000 people without power as of 11:30 a.m. local time on Monday, many of them in the Sierra Nevada region, according to PowerOutage.us, a tracking website.
While people in the Sierra Nevada contended with deep snow, the Pacific Northwest grappled with an Arctic blast after the storm left several inches of snow across the region during the weekend.
For the second day in a row, Seattle broke a record on Monday for lowest temperature on that particular day.
At the Seattle-Tacoma International Airport, a low of 17 degrees was recorded on Monday, Mr. Orrison said. That broke the record of 20 degrees for the day in 1968, he said, adding that the temperature could fall further later on Monday.
On Sunday, it was 20 degrees at Sea-Tac, breaking the record of 22 degrees in 1948, the Weather Service said.