Cars are submerged in floodwater Monday in Windsor, California.
CNN  — 

Much of California can’t soak up another drop of rain. Yet the state is getting pummeled again with torrential downpours and ferocious winds, causing power outages and treacherous travel conditions.

More than 34 million Californians were under a flood watch Monday – about 90% of the state’s population and 10% of the US population.

Parts of the central California coast got walloped with 1 to 1.25 inches of rainfall per hour, the Weather Prediction Center said. Extensive rainfall there Monday triggered significant flooding, mudslides, debris flows and closed roadways.

Widespread rainfall totals of 3 to 6 inches have been observed from just south of San Francisco to just north of Los Angeles. Isolated amounts of 6 to more than 10 inches have been observed in the higher terrain near the coast.

As the rain shifted slowly to the south Monday toward Los Angeles, the National Weather Service there warned of the risk of flooding, debris flow in land scarred by recent wildfires and an increased risk of rock and mudslides in mountains and on canyon roads.

A flash flood warning is in effect Monday evening for downtown Los Angeles until midnight local time, an area including more than 7 million people.

And hurricane-force wind gusts topping 74 mph thrashed states across the western US. More than 37 million people were under wind alerts Monday in California, Nevada, Oregon, Washington, Utah, Arizona and Wyoming.

A 132-mph wind gust lashed Oroville, California. Residents in Washoe City, Nevada, were hit with a 98-mph gust, the Weather Prediction Center said.

TRACK THE STORMS

“Expect widespread power outages, downed trees and difficult driving conditions,” the National Weather Service in Sacramento tweeted. “Now is the time to prepare if you have not already!”

Almost 92,000 homes, businesses and other power customers had no electricity Monday evening, according to PowerOutage.us.

And the central California coast could be at risk of a tornado, CNN Meteorologist Dave Hennen said.

Floodwater rises Monday in a neighborhood in Aptos, California.

The severe weather is part of a relentless parade of atmospheric rivers slamming the West Coast.

California is now extremely vulnerable to flooding because much of the state has been scarred by historic drought or devastating wildfires – meaning the land can’t soak up much rainfall.

And after an onslaught of storms since late December led to deadly flooding, Gov. Gavin Newsom warned Sunday: “We expect to see the worst of it still in front of us.”

‘A high-impact event’

Two bouts of major rainfall are expected to hammer the West Coast over the next few days – without much of a break between events for the water to recede.

The system is part of an atmospheric river – a long, narrow region in the atmosphere that can transport moisture thousands of miles, like a fire hose in the sky.