LOS ANGELES — California's 11th atmospheric river storm of the season barreled through a beleaguered state Tuesday, dropping more rain and snow and sending thousands of residents once again scrambling for higher ground.
At least 16 locations along major rivers were overflowing their banks as the high-impact storm moved south through the state, including areas along the Salinas, Sacramento and Merced rivers. The Pajaro River, which suffered a levee breach from a similar storm last week, continued to spill water onto neighboring farmlands and communities.
At least 70 flood watches, warnings and advisories were in effect statewide, as were avalanche warnings in portions of Mono and Inyo counties and the Lake Tahoe area, according to the National Weather Service.
"The storm will create considerable to locally catastrophic flooding impacts below 5,000-feet elevation and is expected to shift south across much of the California Coast, Central Valley and the Sierra Nevada foothills" Tuesday into Wednesday, the agency said.
More than 500 people took refuge from the storms in about 30 American Red Cross-affiliated shelters Monday night, said Nicole Maul, a spokeswoman for the agency.
In the San Francisco Bay Area, the storm was causing minor urban flooding, road closures, downed trees and gusty winds of up to 50 mph, according to meteorologist Eleanor Dhuyvetter. A ground stop was ordered at San Francisco International Airport on Tuesday morning due to strong winds.
In Monterey County, where a farm town was already inundated by the Pajaro River, more than 10,000 residents were under evacuation warnings and orders due to the surging Salinas River. County officials feared that more flooding could lead to significant crop loss in the heavily agricultural region.
Up to 6 inches of rain could fall before midnight in the Santa Lucia Mountains, which includes part of the Salinas River watershed, Dhuyvetter said.
"The chances for the Santa Lucias to still get a good amount of rain do exist, so we could still see some impacts along Salinas River," she said. "We're just going to have to watch and see how much rain does fall across those mountains."
Evacuation warnings were issued for the Watsonville area of Corralitos Creek on Tuesday, and all schools in the area were closed.
In the Sacramento area, officials warned of high winds and heavy precipitation, with the heaviest rain likely in Shasta County and over the foothills and northern Sierra Nevada.
Farther inland, flood advisories were in effect from Bakersfield to Yosemite, with a high risk of of flash flooding east of the Fresno area, said Jim Brusda, a meteorologist with the weather service in Hanford. Up to 1.5 inches of rain are possible across much of the Central Valley.
"The soil just can't absorb all the new rain that we're going to get, and that's the problem," Brusda said. "The rainfall might be a little bit less than last week, but the impacts are going to be the same, if not more, because the rivers and creeks are already so high, and the ground is already saturated."
Rivers of concern in the area include the Merced River at Stevinson, Bear Creek at McKee Road, and the east-side bypass of the El Nido River, all of which are "right at flood stage," he said.
Precipitation totals increase significantly east of the California 99 corridor — including up to 4 inches of rain in the southern Sierra and more than 2 feet of snow in mountain areas around 7,000 feet, Brusda said. Areas at 8,000 feet or high could see more than 6 feet of snow.
The atmospheric river storm, which is drawing moisture from Hawaii in a phenomenon sometimes referred to as a "pineapple express," was rapidly moving south, raising concerns of flooding in burn scars and more snow on Southern California's already covered mountains.
Flood watches are in effect in San Luis Obispo, Santa Barbara, Ventura and Los Angeles counties through Wednesday morning. Up to 4 inches of rain could fall in Santa Barbara and western Ventura County, said Ryan Kittell, a meteorologist with the weather service in Oxnard.
Santa Barbara County officials have issued a mandatory evacuation order for residents in areas around the burn scars of the Thomas, Alisal and Cave fires, advising residents to leave immediately. Burn scars are known to be waxy, water-repellent and highly vulnerable to debris flows and other hazards.
"The threat for significant roadway flooding and small creek flooding is high, so we would expect a lot of significant road delays and even some closures," Kittell said. The worst of the storm is expected in Santa Barbara and Ventura counties Tuesday afternoon and evening, and in Los Angeles later Tuesday night.
There are moderate threats for river flooding in the region, including along the Ventura, Sisquoc and Santa Ynez rivers, Kittell said. The San Gabriel and Los Angeles rivers "will definitely have a lot of flow, and that usually will result in swift-water rescues, especially in homeless encampments."
Meanwhile, residents in the San Bernardino Mountains braced for more rain and snow — even as some people remain trapped from previous snow storms. At least a dozen people were found dead after those storms blocked roads and left people stranded and unable to dig out from their homes.
"Significant" rainfall totals are expected above 3,000 feet, said Philip Gonsalves of the weather service in San Diego, which covers the San Bernardino area. "We're looking at anywhere from 2.5 to locally 5 inches," he said. Snow is expected around 8,000 feet or higher.
"The bad news is that this event is going to dump a lot of rain on the remaining snowpack, and the snowmelt is going to contribute to the threat of flooding, or debris flows and rockslides and whatnot over the next 18 hours," Gonsalves said.
Flood watches are in effect across the San Bernardino, Riverside and Santa Ana mountains, as well as portions of the Inland Empire "in close proximity to the foothills" and inland Orange County until Wednesday afternoon, he said.
"It has been an active season," he added.
The storm arrives amid near-record snowpack and one of California's wettest winters in recent memory. Nine back-to-back atmospheric river storms hit the state in late December and early January, and a 10th deluged the state last week.
Though conditions are expected to clear after the storm, the relief will be short-lived as yet another atmospheric river has set its sights on California next week, forecasters said — just in time for the first day of spring.
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(Los Angeles Times staff writers Susanne Rust and Terry Castleman contributed to this report.)
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