Big rain and snow could hit California around Christmas, risking floods, landslides and snarling travel

Big rain and snow could hit California around Christmastime, ending a long dry spell for the state.

There’s a high risk for heavy rainfall along the entire California coast between Dec. 23 through Christmas Day, the National Oceanic and Atmospheric Administration’s Climate Prediction Center said. There’s also a high risk of heavy snow along the Sierra Nevada.

The rains would be fueled by atmospheric river storms, which pounded the Pacific Northwest earlier this month, causing flooding and evacuations.

The Climate Prediction Center warned of possible flooding, landslides and difficult travel conditions over mountain passes. Areas at risk include recently burned areas, which could see rapid flows of mud and debris. High winds and heavy rainfall or snowfall could result in power outages, officials said.

“Pretty much all the ensemble projections bring widespread rain sometime in the Dec. 23-26 window, which will certainly bring impacts to the busy Christmas holiday,” said the National Weather Service in Oxnard, which issues forecasts for Los Angeles County.

About 1 in 5 forecast projections expect a strong storm with rain totals of 4 or more inches. It’s still very early to be a definitive forecast, however, and things could change, “but if nothing else, be prepared for at least some rain around Christmas,” the weather service said.

The National Oceanic and Atmospheric Administration’s Climate Prediction Center forecasts a high risk of heavy precipitation along much of California’s coast between Dec. 23 and Dec. 25.

(Climate Prediction Center)

But until then, conditions should remain dry through the current week, with warmer-than-usual temperatures across the Southland. High temperatures are expected to hover between 75 to 85 degrees through the workweek, which is 10 to 20 degrees above normal, the weather service office in Oxnard said.

Temperatures could hit 77 degrees in Anaheim on Tuesday, 78 in Escondido, 81 degrees in Ontario, 82 degrees in Riverside and 83 in San Bernardino. Even Big Bear Lake is expected to see a high of 65 degrees.

Winds in Southern California could pick up in the middle of the week, affected by storm systems coming into Northern California. Winds could come from the north and northeast, with gusts as strong as 50 mph in some north-south corridors, such as the Grapevine section of Interstate 5, the Santa Monica Mountains, the Santa Susana Mountains and the Santa Ynez Range.

Winds could push into the valleys, as well as the Los Angeles Basin and the Malibu area. “Thankfully, with the recent rains, the risk for large fires is really small, but we could see some isolated tree damage and power outages as a result,” the weather service’s Oxnard office said.

Unlike in Southern California, Northern California may start seeing some rain and snow this week.

The North Coast is expected to get the most rain, with the heaviest rainfall in Humboldt and El Norte counties. Through Wednesday, 1 to 1.5 inches was expected in the Fort Bragg area, 1.5 to 2 inches in the Eureka area and 2 to 3 inches in Crescent City. Forecasters warned about the possibility of rock and mudslides.

The San Francisco Bay Area is expected to see light rain this week, with maybe one-tenth of an inch of rain in San Francisco Tuesday through Wednesday, and maybe half an inch to 1 inch between late Thursday through Saturday.

This week is not expected to bring much snow to the Lake Tahoe area. Around midweek, snow levels are expected to remain 9,000 feet above sea level, limiting snowfall — a dusting of up to 4 inches — at only the highest Sierra peaks, the weather service office in Reno said. But winds could be intense, with gusts reaching 100 mph by Wednesday morning, and travel could be difficult on routes such as U.S. 395, the main route between Mammoth Mountain and Southern California.

The weather pattern is expected to shift in the Bay Area on Sunday, when a series of storms that could last through Christmas start to arrive. The weather service office in Monterey, which issues forecasts for the Bay Area, warned that Christmas week’s rainfall totals could result in flooding of roadways and streams and could disrupt holiday travel.

How severe the rain could be for various parts of the stateCalifornia depends on the exact track of the atmospheric river as it heads to California Christmas week.

“Exact timing and amounts are not clear at this time — keep checking back!” the weather service office in Monterey said.

After significant rain in mid-October and mid-November, the skies have been dry in much of the state. The last time downtown Los Angeles saw any rain was on Nov. 21; in San Francisco, it was on Nov. 20.

Parts of the slopes are barren at Snow Summit on Dec. 4 in Big Bear Lake. The low snow levels have delayed the openings of Southern California ski resorts.

(Gina Ferazzi/Los Angeles Times)

California’s ski resorts have been lamenting the warm temperatures and lack of natural snow thus far this season. Some ski enthusiasts were holding out hope for a Christmas miracle.

The storms that are expected to arrive around Dec. 23 “could drop a lot of snow if the forecast holds, and this is the Christmas miracle period that most forecasters are focused on,” the Palisades Tahoe weather blog said Monday. “We’ll continue to watch the trends closely as this period moves out of the fantasy range and into the one-week window by the end of this week. That will increase confidence in big snowstorms if the current forecasts hold.”