A powerful blizzard that has already dumped 3 feet or more of snow across the Sierra Nevada range created life-threatening conditions on a major California highway artery, forced closures and delays at Tahoe ski resorts and plunged thousands of residents east of Sacramento into the dark on Saturday.

And it’s not letting up.

The fierce winter storm brought treacherous spinout conditions to Interstate 80 over Donner Pass, the region’s major east-west roadway, beginning Friday night, stranding vehicles and leaving authorities with no choice but to close the freeway.

I-80 as of Saturday morning was closed in both directions from Colfax to the Nevada state line, said Caltrans and CHP, as both agencies worked to retrieve cars and tractor-trailers left stranded when conditions quickly deteriorated.

“A mass amount of vehicles” were abandoned Friday night over Donner Summit as emergency personnel ferried motorists to safer locations amid whiteout conditions. “It took several hours for emergency personnel and tow trucks to reach motorists,” the CHP’s Truckee office said in a series of social media posts. “There is no estimated time of reopening the freeway, so we suggest you stay home. Stay warm and don’t put yourself and your family in a dangerous situation.”

Officials were expected to work through the day recovering vehicles left on the road.

However, traffic was being held indefinitely and officials weren’t sure when the road would be safe to open.

Caltrans outpost affected by storm

The storm’s severe winds also knocked out power at Caltrans’ fortified nerve center just west of Donner Pass.

“Power is out at our Kingvale office. Not only are the cameras affected so are the message boards,” Caltrans District 3 said in a social media post. “At this point, we are only allowing first responders and Caltrans employees on I-80. No essential big rigs, no ski resort employees. All others will be on a case-by-case basis.”

The Kingvale Maintenance Station, the crown jewel of Caltrans’ roughly 350 maintenance stations since the 1960s, can accommodate and feed as many as 160 workers. It’s also home to a massive repair station, a communications center and “Snowfighter University,” the highway department’s elite training program where Caltrans workers can learn the latest in snow-clearing techinques.

Other Sierra roadways, Caltrans said, weren’t in much better shape, and officials cautioned tractor-trailer drivers and others to avoid using smaller highways to bypass closures.

Highway 50 traffic was being held eastbound at Echo Summit and westbound at Meyers, officials said Saturday morning as snow levels were expected to drop to as low as 2,500 feet, according to forecasts.

Highway 20 was closed to eastbound traffic in Nevada City while Highway 49 was shut down between Downieville and Highway 89 in Sattley. Highway 89 was closed between Emerald Bay and Bliss State Park just after 11 a.m., officials said.

Significant snow totals already

The National Weather Service said Saturday morning that 3½ feet of snow, 42 inches, fell in the 48 hours ending at 10 a.m. at Kingvale. Other impressive totals since the storm arrived included 42 inches at Soda Springs, 39.8 inches at UC Berkeley’s Sierra Snow Lab, 36 inches at Yuba Pass and 35 inches at Sierra-at-Tahoe.

The heaviest totals were square along the highest parts of the I-80 corridor while Alpine, Amador and Tuolumne County locations had received 2 feet or more.

As much as 12 feet of snow could fall in some places by Sunday, forecasters said.

With the snow came extremely dangerous wind gusts on mountain passes. According to reports, winds topped 190 mph at Palisades Tahoe just after 10 p.m. Friday night while neighboring Alpine Meadows recorded a gust of 184 mph. Both gusts were recorded just above 8,600 feet.

Power outages across Sierra counties

The storm, as expected, was created significant power outages in the Sierra. According to data collected by the Governor’s Office of Emergency Services, nearly 23,000 customers living in the High Sierra counties — Alpine, Amador, Calaveras, El Dorado, Mariposa, Mono, Nevada, Placer, Plumas, Sierra and Tuolumne — were without power as of 11 a.m.

Portola in Plumas County (1,551 homes and businesses), areas below Mount Tallac and in South Lake Tahoe (1,253), Alleghany in Sierra County (1,242) and the Rolling Hills section of Georgetown in El Dorado County (1,031) were among the largest swaths without electricity.

Taken together, between 3,500 and 4,500 customers each in El Dorado, Nevada, Placer, Plumas and Sierra counties were off the grid in in PG&E and Liberty Utilities territories before lunchtime, according to the data.

“We are aware of widespread outages,” Liberty Utilities officials said Saturday morning in a social media post. “Crews continue to work around the clock to restore power. Due to poor road conditions, remote access challenges, heavy snow, falling trees, and/or the nature of repairs required, there may be a delay to getting power restored.”

Ski resorts delayed or closed

The blizzard didn’t let up on the constellation of snow resorts across the Sierra.

Several ski resorts were forced to temporarily close Saturday after a perfect storm of bad conditions — heavy snow, gusty winds, tough ice on chairlifts, road closures and power outages, to name a few.

Among those closed: Alpine Meadows, Boreal, Donner Ski Ranch, Homewood, Kirkwood, Palisades Tahoe, Sierra-at-Tahoe, Soda Springs, Sugar Bowl and Tahoe Donner. Many spots, according to OnTheSnow.com, reported receiving a foot or more of snow in 24 hours.

“Safety is our top priority, especially with forecasts of up to 10 feet of snow by Sunday,” Sugar Bowl told fans in a social media post. The resort added that “some essential staff are preparing for reopening tomorrow, but operations are likely to be delayed due to heavy snowfall.”

After delays opening its lifts for several hours, Heavenly and Northstar said they had some runs open amid new snow accumulation of 20 to 27 inches since Friday morning.