USA – At least 3 people were killed by powerful storms in California on Thursday Dec. 25 – a storm that triggered power outages, floods and mudslides.

Heavy rain driven by multiple atmospheric rivers swept across Southern California and the San Francisco Bay Area, dumping up to 11 inches (27 centimeters) of rain in parts of Los Angeles County and prompting evacuations, according to the BBC and ABC News.

California Governor Gavin Newsom declared a state of emergency on Wednesday in Los Angeles and several other counties as emergency crews carried out water rescues and cleared debris-clogged roads.

A 64-year-old man in San Diego was killed by a falling tree on Wednesday, police said.

Another man, age 74, died in the city of Redding after becoming trapped in a vehicle during flooding over the weekend, while a woman in her 70s was swept into the ocean by a large wave at MacKerricher State Park in Mendocino County, the sheriff’s office said.

The US Weather Prediction Center warned that “Numerous flash flooding events are possible,” adding: “Many streams may flood, potentially affecting larger rivers.”

In burn-scarred areas near Los Angeles, including Altadena, mudslides were reported where vegetation destroyed by January wildfires left hillsides unable to absorb rain, CBS News reported.

Los Angeles Mayor Karen Bass urged caution during the busy travel period, saying: “I am urging all Angelenos to stay safe and be extremely careful on the roads if you absolutely must travel. Please do not take this storm lightly.”

More than 100,000 customers were without power statewide as of Thursday evening, while wind gusts in the San Francisco Bay Area exceeded 100 miles per hour (161 kilometers per hour), the San Francisco Chronicle reported.

Forecasters warned that additional rainfall could worsen flooding risks through Friday.