Blizzard warning for Sierra Nevada as California storm closes in

There are few places in the United States that receive more snow than the Sierra Nevada, and that’s exactly where a “life-threatening” blizzard is about to strike. A doozy even by Sierra standards, the massive winter storm is set to drop 5 to 12 feet of snow, which will combine with winds over 55 mph to bring about whiteout conditions as well as “extensive tree damage and extended power outages,” according to the National Weather Service.

Blizzard warnings have been hoisted for much of the Sierra Nevada, including the Northeast Foothills, Motherlode and western Plumas and Lassen counties above 2,000 feet in elevation. They cover ski resorts such as Mammoth Mountain and Palisades Tahoe, and stretch as far north as an area near Redding, Calif. Farther north, winter storm warnings blanket the high terrain.

The days-long winter storm will be caused by persistent Pacific moisture steered ashore by a slow-moving upper-air disturbance. Moderate to heavy snow will fall between Thursday and Sunday, with the worst conditions Friday and Saturday, when winds will be the strongest.

“Sierra travel will be treacherous, with a period of life-threatening blizzard conditions sandwiched in for Friday afternoon through Saturday morning,” the Weather Service forecast office in Reno wrote. “Travel is highly discouraged in these conditions.”

The Weather Service office in Sacramento warned that, starting as soon as Thursday afternoon, mountain travel will become “extremely dangerous to impossible.”

“Do not take this storm lightly,” the Reno office wrote.

“Whiteout conditions are very disorienting, so this is not the time to gamble with you or your family’s lives,” it said. It also warned of closed roads, and air travel delays and cancellations.

The Eastern Sierra Avalanche Center issued an Avalanche Watch for the eastern slopes of the Sierras from Friday to Sunday. “Very dangerous avalanche conditions are expected from Friday afternoon through Sunday morning,” it wrote.

The storm comes exactly a year after the Sierras were buried by heavy snow and also placed under a blizzard warning — but conditions are expected to be worse with this event.

“This is a little different — it’s a lot heavier and a lot more snow,” Robert Baruffaldi, a senior meteorologist with the Weather Service in Sacramento, said in an interview. “If you’re living in the mountains, you could be snowed in for a week potentially. And if the power goes out, hopefully you have a lot of firewood.”

The setup

Unlike atmospheric rivers, which are dense plumes of robust tropical moisture that can stretch thousands of miles, this setup is comparatively tamer from a moisture standpoint for California (just a minor atmospheric river will hit the Pacific Northwest and very far Northern California). In fact, the amount of humidity contained in the air isn’t exceptional — that’s why flooding isn’t anticipated at lower elevations such as the Sacramento Valley.

Instead, it’s a persistent flow of moisture curling east around a zone of low pressure at high altitudes. The upper-level low will meander east from offshore of Vancouver Island and come ashore over southern British Columbia.

Around it, the jet stream will dive and slice east, acting as a conveyor belt to pump the moisture into the mountains. This conveyor belt is moving so quickly that the moisture is constantly replenished. (Picture the factory scene from “I Love Lucy” — even though there aren’t many chocolates on the conveyor belt at any given point, it becomes overwhelming when the conveyor belt speeds up.)

The mountains too will poke into the strong jet stream, meaning the high terrain will be subjected to very strong winds. That will whip the snow around and knock visibilities below an eighth of a mile, if that.

“There are only so many ways that we can say it will be treacherous to be traveling on the roads or even exiting your home during this time frame,” the Weather Service in Reno wrote.

Share this articleShare

The forecast

Conditions will deteriorate during the day Thursday, becoming especially bad later Friday into Saturday, then easing Sunday. At the storm’s peak Friday evening into Saturday morning, snow could fall at rates of 2 to 5 inches per hour, the Weather Service said.

“Snow levels will start out around 5,000 to 6,000 feet today, lowering to 3,000 to 4,500 feet Friday, then down to 1,000 to 2,000 feet Saturday,” the Weather Service office in Sacramento wrote. The lowest snow levels will be found in northern regions, such as Shasta County.

As for snow totals, the Weather Service in Sacramento is forecasting “5 to 10+ feet for elevations above 5,000 feet, locally higher amounts of 12+ feet are possible at peaks, with significant disruptions to daily life likely,” it wrote.

The Central Sierra Snow Lab at Donner Pass, which is operated by the University of California at Berkeley, wrote on X that it could see 7 to 9 feet of snow through Sunday and that it has a chance to post its snowiest day on record.

Most of the high terrain will see winds of 55 to 75 mph, with gusts of 125 mph or higher near ridge tops.

How this snow will help water resources

The Sierra snowpack is a reservoir for water, a precious resource in California. This year, the snowpack is running a bit below average.

That means the forthcoming blockbuster storm is welcome, considering the bleak start to this year’s snow season. Statewide snowpack was just 28 percent of normal Jan. 1. It’s now at 82 percent and climbing because of an active storm track directed into California during February. Multiple feet of new snow in the coming days could fully lift the region out of those deficits.

El Niño-fueled storms have largely targeted the coasts this winter. Some parts of coastal Southern California have seen nearly double their normal rainfall so far this year, along with damaging floods and mudslides.

This week’s bounty for the Sierra is the result of a much colder air mass combined with a storm track farther to the north. The latest outlooks suggest that the snowy pattern could continue at least into mid-March. Snowpack usually peaks around April 1, which marks the beginning of the melt season.

“The season has panned out really, really well compared to what it could have been,” Andrew Schwartz, lead scientist and manager of the Central Sierra Snow Lab, said in a briefing last week. “We have seen the snowpack really bulk itself up compared to those early-season numbers.”

Jason Samenow contributed to this report.

ncG1vNJzZmivp6x7uK3SoaCnn6Sku7G70q1lnKedZMSmrdOhnKtnYmV%2FdXuPa2ZrcF%2Botqa%2B0Zpkp52mlrGiecGloLOykaexbsPAq6WippdiwK%2B71mg%3D