Residents hunkered down, ski resorts closed up shop, and snowplows hustled to clear roads as an enormous snowstorm descended on the Sierra Nevada on Friday, including the Lake Tahoe area, with as much as 12 feet of snow expected at the highest elevations and winds gusting over 100 miles an hour.
The Sierra Avalanche Center warned that the danger of avalanches was high for the Central Sierra. Officials at Yosemite National Park said the park would remain closed through noon on Sunday. Many ski resorts in the region announced that they were closing at least for the day.
The storm system triggered a rare tornado that touched down in Madera, in central California, damaging an elementary school while students were inside on Friday, said Brian Ochs, a meteorologist at the National Weather Service in Hanford.
As showers and heavy snow continued Friday evening, more than 57,000 California customers had no electricity, according to PowerOutage.us. In Tahoe City, where there were reports of brief power outages, the streets were mostly empty of cars as snow piled up the roadways. One resident, Tristan Queen, said he was planning to head to the grocery store by snowmobile.
“It’s definitely for the novelty, but sometimes it actually feels like a safer, smarter way to travel because then you’re not going on the roads and you’re letting the plows do their thing,” said Mr. Queen, 42, who runs a local belt company.
Meteorologists began sounding the alarms earlier this week about “life-threatening blizzard conditions” expected through Sunday in the Sierra Nevada, the huge and varied mountain range that runs along the spine of California.
On Friday evening a section of Interstate 80, a major artery through the Sierra, was closed indefinitely because of “spin outs, high winds, and low visibility,” the California Highway Patrol said.
By Thursday, forecasters were urging drivers to avoid traveling in the blustering winds with minimal visibility. “Your safe travel window is over in the Sierra,” the National Weather Service in Reno, Nev., posted on social media. “Best to hunker down where you are.”
One resort, Palisades Tahoe, said it had seen “intense” snowfall and winds of 100 miles an hour on Thursday night. In videos posted on social media by the resort, ski lifts were faintly visible through a blanket of white, and the sky and ground were indistinguishable from each other.
The resort, which was packed last weekend for a major ski competition, had become “an absolute ghost town” by Friday, said Veronica Berkholtz, a manager of the coffee shop at Palisades Tahoe. The resort said it would also be closed on Saturday.
Conditions were expected to continue deteriorating into the night as a cold front moved in, said Justin Collins, a meteorologist with the Weather Service in Reno. That could mean five more feet of snow on mountain crests, in addition to the snow that had already fallen.
He said that snow was expected to continue falling heavily on Saturday morning before “lightening up a little bit” in the afternoon.
Forecasters reserve blizzard warnings like the one that was in effect on Friday for only the most severe snowstorms. The Weather Service in Reno has issued only eight blizzard warnings in the last 12 years.
The last time there was a similar warning was almost exactly a year ago, when a powerful snowstorm dumped more than two feet of snow on the Lake Tahoe area in less than a day. The snow piled up so thickly on rooftops that when another storm threatened more snow and rain, residents had to scramble to shovel off enough weight to keep their roofs from caving in.
The same storm system caught officials and residents in the San Bernardino Mountains of Southern California off guard, trapping people for days in houses that were buried to the eaves in snow.
In the villages surrounding Lake Tahoe, residents and business owners say that they know how to prepare for lots of snow.
“It becomes part of the winter experience,” said Heather Svahn, the president of Mountain Hardware & Sports, a store in Truckee, Calif., that sells items including fishing gear, shovels and power tools.
Ms. Svahn said the store had arranged for extra supplies to be delivered earlier in the week, to avoid the most treacherous travel periods. Residents have been stopping into the store, she said, to buy shovels and shear pins, special bolts for snowblowers that are prone to breaking when the machines are used in heavy, wet snow conditions.
Shannon Parrish, the owner of Grocery Outlet, which has stores in Truckee and in Incline Village, Nev., said that both stores were open on Friday morning, but that the situation could change quickly. Deliveries were canceled for Friday and Saturday, she said, and employees who commute from Reno were told to stay home.
Ms. Parrish, who lives in Truckee, said eight to nine inches of snow had fallen at her house by Thursday night.
“It’s really quiet,” she said. “I think people are prepared to wait it out.”
But locals are also beginning to look ahead to this year’s ski season. Palisades Tahoe, the resort, announced that it would be open until the end of May.
“It’s just great fun,” said Dave Wilderotter, the owner of Tahoe Dave’s, a ski and snowboard shop with several locations in the area. “It’s just fun to be able to ski in the morning and golf in the afternoon.”
On Friday, a few visitors in Tahoe City got an early start, skiing in the backyard of a rental house before the storm worsened.
John Yoon contributed reporting.