Powerful Storm Threatens California With More Flooding

SACRAMENTO — A powerful storm swirled over the California coastline on Wednesday, threatening more flooding, landslides and damaging winds across the state just days after it was drenched by another “atmospheric river.”

Usually, rainfall amounts like those expected this week would not have a significant impact. But the rain over the past weekend left the ground across much of California saturated, like a wet sponge, forecasters said, making the state more susceptible to flooding and rapid runoff.

That has left officials up and down the coast to contend with repeating deluges in a state that has spent much of the past several years dealing with drought and wildfires.

Gov. Gavin Newsom declared a state of emergency throughout California on Wednesday in order to more quickly marshal a storm response.

Nancy Ward, the new director of the governor’s office of emergency services, warned of flooding, mudslides and power outages. “We anticipate that this may be one of the most challenging and impactful series of storms to touch down in California in the last five years,” she said.

Preparations were in full swing across the state on Wednesday. In Northern California, several parks were closed, and conservationists said they were monitoring fire-damaged redwoods in the Santa Cruz Mountains because the strong wind gusts could topple trees. In San Francisco, city officials scrambled to secure enough sandbags for residents. Evacuations were ordered in parts of Santa Cruz County, south of San Francisco. And in flood-prone San Mateo County, many students were asked to head home early on Wednesday and to not return to school on Thursday.

Flood warnings were in place north of San Francisco, and flood watches were in effect across Southern California. Rainfall was forecast to start slow, and then become heavier throughout Wednesday, accompanied by strong winds and thunderstorms. About 60,000 utilities customers were without power in California on Wednesday afternoon, according to PowerOutage.us, which tracks outages.

“Don’t let your guard down,” the National Weather Service warned.

At a neighborhood in the Bay Area city of Richmond, local officials worked on Wednesday to head off a landslide. Mayor Tom Butt said that a resident warned him on Tuesday about some scarp and rocks falling from a hill, which was saturated and visibly cracked after days of rain.

Nearby residents were evacuated, and on Wednesday morning contractors in hazmat suits worked to position a tarp on the hill to divert the rain to a nearby pond.

“Hopefully they can get that plastic up there and keep enough water out of the hill, to keep the slide from getting worse,” Mr. Butt said. “We’re doing all we can do,” he added.

In Sacramento, where forecasts called for up to three inches of rain in a region that was already inundated by a storm on New Year’s Eve, homeowners faced more power outages and flooding.

Ramona Saunders, 64, a retired government worker, stood shivering in a pelting rain outside a hardware store near her home in Carmichael, planning to buy flashlights and batteries. She said that a pepper tree outside her house had already blown over in the New Year’s Eve storm, and she was worried that the maple in her front yard would be next.

“I keep thinking, ‘Please don’t let this be the storm,’” she said. “I just don’t want to be on the 6 o’clock news.”

In the Mission District of San Francisco, doors of apartment buildings, coffee shops and restaurants were blocked by sandbags as residents awaited the storm.

Several streets in the low-lying neighborhood already experienced flooding over the weekend. But some stores, including King’s Refrigeration and Appliances, opened for business anyway.

Refrigerators that had been displayed on the sidewalk there began to float away in the pooling water on Saturday, said Jose Gomez, whose father owns the shop. “We had to hold them down so they didn’t get taken away in the current,” he said.

But Mr. Gomez was hopeful about the coming storm and said there were no plans to cut back hours. “Maybe it won’t rain that much,” he said.

The storm is expected to bring up to four inches of rain and winds of up to 40 miles an hour to California’s inland valleys, and gusts of 60 to 80 m.p.h. in the coastal hills, according to the Weather Service.

In the mountains, heavy snow is expected. Water officials said on Tuesday that the statewide snowpack was at 174 percent of the average for the date — a silver lining to the storm pummeling drought-stricken California.

The snowpack in the Sierra Nevada mountain range supplies about 30 percent of the state’s water, according to the Department of Water Resources. The snowcaps act as crucial water storage until they melt during drier, warmer months, sending fresh water into the state’s rivers and reservoirs.

And the heavy rain and snow have brought a measure of relief to drought-plagued California, especially in its agricultural industry, the nation’s largest. “This is really a godsend, just to see these storms lining up and hitting California dead-on,” said Don Cameron, whose Terranova Ranch grows produce on 8,500 acres in the southern San Joaquin Valley.

Still, water experts have cautioned that no matter how much precipitation there is in the coming days, residents should still plan to conserve. They have pointed to the fact that in 2021, significant December snowfall gave way to the driest January, February and March on record, leaving Californians to navigate increasingly dire warnings and water-use restrictions throughout the summer.

And with more storms on the horizon, the mountains could see more rain that may lead to flooding.

“Now that we have a saturated snowpack, we’re probably not going to get a lot more storage from the rain that falls on it,” said Andrew Schwartz, the lead scientist and manager at the Central Sierra Snow Lab of the University of California, Berkeley. “Meaning that if we do get rain, it’s likely that we will see some additional melt. So we’re really just crossing our fingers that it stays as snow.”

The situation underscores California’s water conundrum: The state desperately needs a very wet winter, but any time it is drenched by a big storm, there is also a risk of damage and chaos.

“This is a prime example of the threat of extreme flooding during a prolonged drought as California experiences more swings between wet and dry periods brought on by our changing climate,” Karla Nemeth, director of the Department of Water Resources, said in a statement.

The latest storm is part of a series of atmospheric rivers — channels of moisture from the tropical Pacific Ocean — that meteorologists expect will continue until mid-January. “The message to convey is resiliency, as this is not a ‘one and done’ storm,” the Bay Area office of the Weather Service said on Wednesday morning.

The atmospheric river that drenched the West Coast last week killed at least five people. Another storm system soaked California again before barreling east across the country on Tuesday, spawning strong tornadoes, thunderstorms and flooding in parts of the Plains, Upper Midwest and South after dropping snow on Utah and Arizona.

That storm was expected to decrease in intensity as it moved toward the East Coast, the Weather Service said. More rounds of heavy precipitation are expected to hit California on Saturday, and again on Monday.

Shawn Hubler reported from Sacramento, Soumya Karlamangla from San Francisco and Jacey Fortin from New York. Reporting was contributed by Julie Brown, Derrick Bryson Taylor, Jill Cowan, Christine Hauser, Judson Jones, Holly Secon and John Yoon. Alain Delaquérière contributed research.