Disastrous flooding could hit parts of California this weekend, forecasters warned Friday, as the eighth storm in succession barreled in over land already too waterlogged to soak up any more rain.

The most populous US state has been pummeled by near-record downpours over a very wet three weeks, which have already caused flooding, landslides and widespread power outages.

At least 19 people are known to have died as communities struggle to cope with the constant deluge.

On Friday yet another system moved in, with forecasters warning the Monterey Peninsula could be cut off and the whole city of Salinas -- home to 160,000 people -- flooded.

"The entire lower Salinas Valley will have disastrous flooding," the National Weather Service said.

"The entire city of Salinas is in danger of flooding. Most of Castroville will flood. All roads near the Salinas River will be flooded and impassable. 90,000 acres or more of agricultural land in the Salinas Valley will have disastrous flooding.

"Many roads, homes and agricultural land areas in the Salinas Valley will have major flood damage."

The Salinas River, already swollen by weeks of torrential rain, was expected to peak some time Friday, breaching its banks in a flood that could last until Sunday.

Kelley O’Connell said the bursting of a levee near her home had worried her.

"If they release water from the dams or we get more rain, we’re just a field away," she told the San Francisco Chronicle as she collected sandbags.

Evacuation orders and warnings were widespread, with forecasters saying major roads could become impassable -- including highways that link the Monterey Peninsula with the rest of the county.

"Residents both on the peninsula and in the Salinas area should expect to be cut off for two to three days," Monterey County officials said earlier this week.

Monterey County Sheriff Tina Nieto told reporters Thursday that floodwater could strand people.

"This is a slow-moving event" and not all places will be impacted at once, she said.

"The river crests at different times."

Resident John Guru said he was taking no chances, with four days' supplies at home and two days' worth in his car in case he is caught out on the road.

"I’m not sure how bad it’s going to be," he told the Monterey Herald.

"I will find a place if needed and do whatever it takes," he said, adding: "This is crazy, I was not anticipating anything like this."

Snow

Workers have rushed out in between storms to clear up some of the mess left behind, shoveling mud from roads even in the heart of Los Angeles.

Crews have cut up felled trees, and heavy machinery have been drafted in to move rockslides.

Hundreds of thousands of homes and businesses have been left without power at various times -- sometimes repeatedly -- as rickety infrastructure has taken a battering.

And it's not over yet, forecasters say.

"The ongoing unsettled weather in the West associated with the active Atmospheric River pattern unfortunately continues into this weekend with another couple rounds of heavy precipitation forecast," the NWS said.

Over the mountains, that precipitation was falling as snow, with more than three feet (a meter) expected in the Sierra Nevada range, making travel dangerous or impossible, even as thousands of skiers and snowboarders head for fresh powder over the Martin Luther King, Jr Day holiday weekend.

Among those who have died in the last three weeks were drivers who were found in submerged cars, people struck by falling trees, a husband and wife killed in a rockfall, and people whose bodies were discovered in floodwaters.

Winter storms are not unusual in California, where most of the annual rain comes in a fairly concentrated period.

But global warming, driven by the industrial era's unchecked use of fossil fuels, is supercharging storms, making them wetter and wilder.

At the same time, the western United States is aridifying, with much of the region in its 23rd year of drought.

Hydrologists say the recent rains are helping -- California has received an average of almost nine inches (23 centimeters) of rain since late December -- but are not a fix.

"A few weeks of storms is not enough in this drought for California, but it certainly is nice. It's certainly making a good dent," Jay Lund, director of University of California, Davis, told the Chronicle.

© Agence France-Presse