Storms continue to bring heavy rain and snow to western U.S. — and more is on the way

A swath of the western U.S., from the California coast to Colorado and as far north as Idaho, was bracing for cold temperatures and heavy rain and snowfall as a series of storms driven by Pacific moisture and cold Arctic air continued to pound the region.

A weather pattern that began this week brought pounding rainfall to the California coast, several feet of snow to the Sierra Nevada and record snowfall and freezing temperatures to the Pacific Northwest and Rocky Mountain states, prompting officials to close roads and schools, open emergency warming shelters, and issue warnings of flash floods, mudslides and avalanches.

Michael Schichtel, lead forecaster for the National Weather Service at the Weather Prediction Center, said the current series of storms “rates as probably one of the top 25 of the past century,” given the heavy rain and snowfall.

Schichtel said that a plume of moisture over the Pacific Ocean, known as an “atmospheric river,” flowing inland and hitting the mountains was causing heavy rainfall on the West Coast and snow in the Sierra and Rocky Mountains, with some of the moisture even streaking across the southern Plains.

Schichtel said it wasn’t uncommon for low-pressure systems to interact with moisture in this way during the winter, but he said this latest round of storms was particularly strong.

On Thursday, the Squaw Valley Ski Resort in Lake Tahoe tweeted that it had received 7 feet of snow since Monday. Transportation authorities closed Interstate 80 in the Tahoe-Truckee region on Wednesday because of low visibility and snow.

In Oregon, a 51-year-old homeless man died of hypothermia in Portland on Monday night, after temperatures reached 15 degrees with the wind chill. The city has opened several warming shelters as freezing and sub-freezing temperatures continue.

Also in Oregon, an 8-year-old girl was killed Wednesday night when gusty winds knocked an evergreen tree down onto her home.

In Boise, Idaho, between Tuesday and Wednesday night 15 inches of snow had accumulated on the ground. Ada County, the state’s most populous, saw 105 road slide-offs, 124 stalled or stuck vehicles, and 73 car crashes on Wednesday alone, according to the sheriff’s office.

A brief respite in the wet weather in California and the eastern Sierra was expected Friday, but more storms and snow are expected to return by Saturday.

“There are going to be some places where you’re going to have observations of at least 10 feet of snow,” said Schichtel, adding that 10 or 12 inches of rain — or even more — could fall by the end of the weekend.

Live updates: Winter weather slams California »

Flash-flood and flood-watch advisories were in effect Thursday for large parts of northern and central California as well as parts of western Nevada, where officials had set up stations for residents to pick up sandbags.

Avalanche warnings were issued in parts of Colorado and Utah, and snow was expected to continue in those states, as well as Arizona and New Mexico, through Friday.

Cold, dry weather was forecast in the Pacific Northwest and Idaho on Friday, but a mix of snow, freezing rain and rain was expected to return beginning Saturday, said Jeff Lorens, a meteorologist for the National Weather Service.

nina.agrawal@latimes.com

Twitter: @AgrawalNina

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