The latest storm in a series of “atmospheric rivers” swept much of the state on Tuesday with strong winds, heavy rain at lower elevations and snow in the mountains, worsening flood risks.
LOS ANGELES — Tens of millions of California residents were under extreme weather advisories on Tuesday night, following yet another day of heavy precipitation that forced evacuations and the closures of roads and schools.
As of 10 p.m., power had been restored to most of the more than 250,000 Pacific Gas and Electric customers in the San Francisco Bay Area who lost it earlier in the day. But much of the state was still under flood, winter storm or high wind warnings, according to the National Weather Service.
The brunt of the storm was moving south across Los Angeles and Ventura counties late Tuesday night. Forecasters expected the rainfall to intensify before tapering off later on Wednesday. A flood watch was in effect until Wednesday afternoon for an area of Southern California that included all of Orange County and the mountains of Riverside and San Bernardino counties.
High winds in the Bay Area earlier on Tuesday had interrupted electricity service, forced the city’s airport to briefly pause operations and blew a window out of a downtown skyscraper. No one was injured when that window fell the ground, the San Francisco Fire Department said.
South of San Francisco, water from the Pajaro River in Monterey County breached a levee on Tuesday, forcing the closure of portions of Highway 1 in and around the Big Sur area until officials could clear fallen trees and power lines and assess the safety of bridges.
Pajaro is the latest California community to suffer a levee break in a season when “atmospheric river” storms have been dumping precipitation on a landscape already saturated with water, testing river walls that protect millions of residents from disaster.
The storm that brought high winds and floods to California on Tuesday was expected to cause more flooding as it spread across the Central Valley and into the Sierra Nevada foothills overnight, including in areas that are not normally prone to it, National Weather Service said. A number of the flood warnings were in effect until further notice.
In Oceano, a community in San Luis Obispo County where evacuation orders and warnings were in place overnight, residents said they were worried that a nearby levee that had been damaged by storms in January could fail, as one on the Pajaro River did on Saturday.
“If it does, it will flood here,” Willie Reed, 44, said as he sat on his front porch on Tuesday, watching the rain. Mr. Reed said that he and his fiancée had packed their bags and were ready to go. Near his house, ducks swam across a street already inundated with rain.
Flooding isn’t the only risk. At higher elevations, the latest “atmospheric river” piled more feet of snow on top of already groaning roofs. In many mountain communities, the worry is that the snow could become so heavy that it could cause roofs to collapse.
The leading edge of the storm came ashore the previous night in Northern California, and by late morning on Tuesday had begun to shift the brunt of its impact to the south. The Weather Service said on Tuesday evening that airports in Los Angeles and elsewhere in Southern California had recorded record amounts of rainfall for that day.
As the rain fell, schools were forced to close in a number of communities, especially along the Central Coast, and officials up and down the state issued evacuation warnings for vulnerable spots.
By Tuesday night, those warnings were starting to lift. Santa Barbara County ended its evacuation order for people living near the burn scars of recent wildfires. But Plumas County, north of Sacramento, warned residents living along the Feather River and in other low-lying areas to be ready to head for higher ground.
Concerns about road safety persisted. Sections of highways and roads in some parts of the state were closed on Tuesday by rockslides, flooding and downed trees loosened by the wind and rain, the California Department of Transportation said. Officials warned motorists to avoid driving where moving water covered the pavement.
In Monterey County, a coastal stretch of Highway 1 that includes the iconic Bixby Creek Bridge would remain closed overnight because of risks posed by fallen trees and power lines in the Big Sur area, the state’s Department of Transportation said.
A nearby portion of Highway 1 was closed because of the overflowing levee from the Pajaro River, the Monterey County Department of Emergency Management said. The river’s bridges are stable, but officials said they must be assessed before the highway could reopen.
Monterey was among the counties where Gov. Gavin Newsom declared a state of emergency this month. President Biden has approved a federal emergency declaration for California as well.
The storm on Tuesday was the latest bout of severe weather in what is shaping up as one of the state’s most ferocious winters in recent memory. Previous storms have forced some residents to evacuate from floods and trapped others in their homes beneath mounds of snow.
The southern portion of the Sierra Nevada now has what may be its deepest snowpack on record, according to Daniel Swain, a climate scientist at the University of California, Los Angeles. Scientists say this winter has already been the third snowiest on record for the central Sierra.
There is evidence that the United States can expect more unusual severe storms as the planet heats up, potentially striking in new places or at unexpected times of year.
Katya Cengel contributed reporting from Oceano and San Luis Obispo, Calif. April Rubin contributed reporting from New York.
