A powerful winter storm has been lashing California on Saturday that could cause floods, blizzards and avalanches, and causing frigid temperatures.

Overnight lows could drop below freezing in some areas while downtown San Francisco could see record-breaking cold temperatures Saturday morning, according to the National Weather Service. Projected temperatures of 38 degrees Fahrenheit (3 degrees Celsius) would see the city at its coldest since 2009, the weather service said.

Flash flood warnings were issued from Friday through 1 a.m. or 2 a.m. Saturday in Los Angeles and Ventura counties, a region with some 6 million people. The weather service said flash flooding was occurring late Friday in Ventura County, where up to 7 inches (18 centimeters) inches of rain had fallen and up to 10 inches (25.4 centimeters) were possible before the storm turned showery on Saturday afternoon.

In Los Angeles County, forecasters said life-threatening flash flooding was possible near creeks, streams, urban areas, highways and areas that were burned by wildfires. The threat zone included downtown L.A., Hollywood, Beverly Hills and many suburbs.

“Shallow landslides and mudslides are expected,” the weather service said

Despite the heavy downpour, no serious problems were immediately reported.

Rain falling at up to an inch an hour raised the fear of flooding or mudslides. Evacuation warnings were issued in some burn-scarred areas and for a mile-long stretch of Oceano, which lies on the central coast near a levee that overflowed during storms last month. Residents were urged to be ready to flee at short notice.

Meanwhile, people farther east were struggling to deal with the fallout from storms earlier this week.

More than a half-million people in Michigan were still without power late Friday night, days after one of the worst ice storms in decades caused widespread power outages by knocking down some 3,000 ice-coated power lines.

Promises of power restoration by Sunday, when low temperatures were expected to climb back above zero (minus 18 Celsius), were of little consolation.

“That’s four days without power in such weather,” said Apurva Gokhale, of Walled Lake, Michigan. “It’s unthinkable.”

CURRENTPH NEWS SERVICE