California braces as dangerous storm system set to deliver 'life threatening flooding' and heavy snow

SAN DIEGO — A strong Pacific storm system is expected to bring “life threatening flooding” and heavy snow to California on Sunday and early into the week, according to the National Weather Service.

On Sunday, Gov. Gavin Newsom declared a storm-related state of emergency as federal forecasters said an atmospheric river of precipitation drawn from waters north of Hawaii is producing a firehose of rain and snow for the state. The combination of warm air from the Pacific, strong onshore winds and cooler air onshore could produce thunderstorms as well as a deluge producing as much as 1 inch per hour, they said.

Damaging winds, brief tornadoes and waterspouts were also possible Sunday along coasts and valleys in southwest California, according to the National Weather Service in Los Angeles.

Multiple feet of snow were expected in parts of the Sierra Nevada mountain range.

Newsom's emergency declaration was for San Luis Obispo, Santa Barbara, Ventura, Los Angeles, Orange, Riverside, San Bernardino and San Diego counties. It will allow for activation of the National Guard, if necessary, and facilitate faster recovery efforts, his office said in a statement.

Much of the state is expected to get heavy rain, with estimates increased as the day has progressed: Around 4 to 8 inches was possible in coasts and valleys, and 8 to 15 inches was likely for mountain ranges, National Weather Service meteorologist Robbie Monroe said at an afternoon press conference.

Monroe described the storm, one of several in California this winter that may be influenced by a rainy El Niño weather pattern, as "potentially historic."

A flash flood warning, which means rapid flooding may be underway and those in flood-prone areas should rush to higher ground, was in effect for a wide swath of Santa Barbara and Ventura Counties on Sunday. The warning also covers the northern edge of L.A. County.

Covered communities include Oxnard, Thousand Oaks, Simi Valley, Ventura, Santa Barbara, Camarillo, Lompoc, Fillmore, Ojai, Montecito, Santa Ynez, Point Conception, Chatsworth, Moorpark, Santa Paula, Port Hueneme, Carpinteria, Solvang, Summerland and Rincon Point, the NWS service said.

Heavy rain could bring life-threatening flash, river and urban flooding to the the region, as well as potential debris flows and mudslides, according to the weather service.

The most at-risk communities in California are those on or below hillsides, especially those affected by wildfires, according to the Governor’s Office of Emergency Services.

Residents are encouraged to follow local alerts and seek higher ground and not to walk or drive through debris flows, emergency services spokesperson Diana Ibrahim said in an update.

The storm was sending bands of rain into the Bay area Sunday afternoon as it moved south and east into Santa Barbara and Ventura counties, according to weather service statements and radar. It was expected in Los Angeles in earnest Sunday evening, and in San Diego Monday night, forecasters said.

Mandatory evacuations were ordered for parts of Santa Barbara and Ventura counties. Santa Barbara's public school district said in a statement that its campuses would be closed Monday as a "precautionary measure." At least nine other districts in the Santa Barbara region canceled classes for Monday.

Los Angeles Mayor Karen Bass issued an evacuation order for La Tuna Canyon Road.

"The City urges residents in this area to evacuate immediately," the mayor's office said in a news release. "The area subject to the Order is at an increased risk of significant flooding, mudslides, and sediment flow because of the burn scars left by the Land Fire that occurred in 2022."

The city's Emergency Operations Center was also activated to level 2 Sunday morning.

Los Angeles Unified public schools will be open Monday, but Glenwood Elementary School, at the foot of the Verdugo Mountains, will be shuttered, Superintendent Alberto M. Carvalho said at a news conference.

Sandbags are available for residents in multiple locations, and shelters will be opened for those who need them, the state emergency services office said.

The PGA Tour’s AT&T Pebble Beach Pro-Am in Pebble Beach along the coast was delayed Sunday as a result of the rain and strong winds, The Associated Press reported. The storm system could cut the tournament short.

Damaging wind gusts of up to 95 mph

Damaging wind gusts up to 95 mph may also affect Northern and Southern California through Sunday night, leading to downed trees and power outages, according to the NWS.

Felled trees, utility poles and power lines were reported in the Wine Country city of Santa Rosa north of San Francisco, fire officials said.

A man was injured when a tree fell on an occupied vehicle traveling north on Highway 101 in Santa Rosa on Sunday morning, authorities said. It’s not clear what condition the man was in.

In the San Francisco Bay Area, hurricane-force wind gusts are possible. And to the south, in San Luis Obispo County, wind gusts of 61 mph were reported overnight.

Video showed palm trees swaying in strong winds in Discovery Bay on Sunday morning. Teams with San Francisco Public Works were removing downed trees in West Portal.

San Francisco International Airport issued a ground delay for departures to the airport until early Monday because of wind, according to the Federal Aviation Administration.

Hurricane-force wind warnings were in effect for the waters off Big Sur, south of San Francisco, with wind gusts of 92 mph possible, the NWS said.

A road into Goleta State Park in Santa Barbara County was flooded enough to make driving through it a bad choice, the weather service said on social media platform X.

The weather service said 1 to 3 inches of rain already fell in Santa Barbara and Ventura counties as the storm rotates toward the southeast from the coast.

Snow in the Sierra Nevada

Heavy snow will be the headline event for higher elevations, including the Sierra Nevada and Northern California mountain ranges, specifically above 5,000 to 6,000 feet.

“Snow totals of several feet are forecast for the Sierra through Tuesday morning,” the NWS said. “Heavy snow rates of 2-3"/hour along with strong winds will lead to whiteout conditions and dangerous, near impossible travel conditions.”

Elevations above 7,000 in Southern California may also get heavy snow.

The system is expected to move north and inland and bring “moderate to heavy snow for the regional mountain ranges of the Pacific Northwest, Great Basin, and Northern Rockies over the next couple of days,” the weather service said.

Over 200,000 utility customers did not have power in California as of Sunday evening, according to Poweroutage.us.