Another major storm set to hit waterlogged Northern California and Southland, sparking fears

After a powerful New Year’s storm hits the state, forecasters are warning Californians to prepare for another “rough” weather system that could bring widespread flooding starting mid-week.

After a weaker storm that moved in on Monday, forecasters are focusing on an atmospheric river that is expected to bring heavy rain and strong winds Wednesday and Thursday.

In the Sacramento Valley and northern San Joaquin Valley, forecasters are expecting at least 2 inches of rain, with more than 3 inches in some spots. The foothills could receive 2 to 5 inches of rain, said Scott Rowe, meteorologist with the National Weather Service in Sacramento.

A flood watch will be in effect for virtually the entire Sacramento Valley Wednesday through Friday morning.

“The threat of flooding is going to be renewed at least at this point from an urban perspective, with people living within the city limits, with poor drainage, low areas, low roads, those are certain of our primary concerns right now,” Rowe said.

The midweek storm follows one that hit over the weekend and left tens of thousands of homes in Northern California without power for much of Sunday. Record high water levels on the Cosumnes River near Sacramento breached three levees and flooded the area.

Flash flooding along Highway 99 and other roads south of Sacramento submerged dozens of cars near Wilton, where water spilled over levees. Search and rescue teams in boats and helicopters rushed to retrieve trapped motorists. At least one person was found dead in a submerged car near Dillard Road and Highway 99, according to local media.

Thousands of residents were still struggling with power outages in the Sacramento area Monday morning, according to the Municipal District of Sacramento.

“We have already prepared the ground with the floods last week. We are entering this storm with a whole new set of different circumstances,” Rowe said Monday. “Everything is already wet and well saturated in many cases. It is definitely a situation that we are monitoring very closely.

The bulk of the New Year’s storm hit Northern California.

In San Francisco, 5.46 inches of rain fell, making Saturday the city’s second wettest day in more than 170 years, the National Weather Service reported.

The 101 freeway in south San Francisco was closed for flooding just as New Year’s revelers were leaving to celebrate, but it reopened hours before midnight.

Forecasters warn the Bay Area could be hit hard once again this week.

The National Weather Service’s Bay Area office warned of catastrophic impacts in the area, including “widespread flooding, washed out roads, collapsed hillsides, downed trees (potentially full of thickets), widespread power outages, immediate disruption of trade and worst of all, likely loss of life.

“To put it simply, this will likely be one of the most impactful large-scale systems this meteorologist has seen in a long time,” the statement said. “It really is a brutal system that we are looking at and that needs to be taken seriously.”

Starting Wednesday, the Bay Area could see 2 to 4 inches of rain in lower elevations, with 3 to 6 inches in the coastal hills, said Ryan Walbrun, weather service meteorologist in Monterey.

“For most of the region, it will be similar or even slightly heavier rainfall than what we saw on New Year’s Eve,” he said.

Flood watches and high wind watches were issued for much of Wednesday and Thursday for the entire Bay Area, Walbrun said. Wind gusts will be around 50 to 60 mph.

With the ground already saturated from the weekend storm, Walbrun said, “it just makes it easier for the trees to fall.” And with rivers and streams already flowing higher, “there’s just less capacity to hold all the new water.”

“Much of the Bay Area was hit pretty hard on New Years Eve and is still recovering,” Walbrun said. “We expect this to exacerbate the situation.”

With Tuesday set to be a “break day” for the region, with dry weather, Walbrun urged residents to spend this time preparing for the approaching storm.

“Tuesday is kind of like your last day for basic prep. Sandbags, power outage preparedness,” he said. “I think we can use what we saw on New Year’s Eve as a benchmark and expect similar impacts with this storm on Wednesday and Thursday.”

Some cities were already preparing on Monday.

In Palo Alto, city staff cleared mud and debris from streets near a flood-affected creek. The city of Watsonville, Santa Cruz County, set up sandbag stations, prepared a park to serve as an evacuation shelter, and had crews clear flood-affected areas .

Walbrun warned residents that stronger weather systems are expected this weekend and next week.

“The storms are really lined up, so there just won’t be much of a recovery period,” he said. “We have to be here for the long haul here, [because] it looks like we have two or three more storms after this wednesday, thursday one.

In Los Angeles, where heavy rain fell on New Year’s Eve, forecasters were expecting light rain Monday afternoon, totaling a quarter to half an inch.

But then “attention really turns to Wednesday and Thursday’s storm, which appears to be the strongest of the season,” said David Sweet, a National Weather Service meteorologist in Oxnard.

On Wednesday, an initial frontal system will bring perhaps 1 to 2 inches of rain to the region, with slightly higher amounts in the mountains, Sweet said.

The main storm system, he said, will arrive Wednesday evening and Thursday, bringing with it very heavy rain. Rainfall totals could be 2 to 5 inches at lower elevations and 5 to 8 inches in the mountains, he said.

“Damaging winds and flooding would be the primary concerns for this particular system,” Sweet said. “It’s going to be a tough few days.”

The storm could also bring 50mph winds and would be “very capable of knocking down power lines, trees, tree branches” and causing possible damage in some areas, he added.

There are more possible storms next week, though those systems are likely more focused on areas north of Los Angeles County, Sweet said.

With wind chill temperatures expected to drop below 32 degrees, the LA County Public Health Department issued a cold weather alert this week. The alert will be in effect on Mt. Wilson Thursday and Lancaster Tuesday, Friday and Saturday.

“Children, the elderly, and those with disabilities or special medical needs are especially vulnerable in cold weather,” Los Angeles County Health Officer Dr. Muntu Davis said in a statement. “Extra care should be taken to ensure they don’t get too cold when outside.”

Although California’s drought is far from over, the wet weather that ended 2022 allowed at least some of the state’s major reservoirs to exceed their historic average water supply.

“After years and years of drought, this might bring some relief,” Sweet said. “It’s just a shame that we get so much at once.”