Authorities said torrential rain in Northern California killed two people Thursday after their car was submerged in a flooded underpass and rescuers weren't able to get them out.
An individual called 911 needing to be rescued after they escaped to the roof of their car because the underpass was filling up with rainwater. Firefighters in Millbrae, south of San Francisco, responded to the call just before 6 a.m., said Javier Acosta a detective for San Mateo County Sheriff's office.
Acosta told KPIX it was only after the firefighters entered the water to rescue the person on top of their car that they realized there was a separate vehicle underwater. After rescuing the first person, they tried to gain access into the submerged car but were unable to.
"The conditions changed rapidly and it became too dangerous for the responders," he said.
Acosta told KTVU the two people in the vehicle had driven through a lot of water and "the water was rising rapidly," he said.
After several hours of draining floodwater from the underpass, firefighters then discovered the two bodies.
"At this time we don't know exactly what happened, however, there was heavy rain this morning," Acosta told KPIX.
An investigation into the incident is underway.
Authorities on Thursday urged residents of several Southern California mountain and canyon communities to voluntarily leave their homes because of possible mud and debris flows.
The precautions for Southern California came as precipitation that had mostly been falling in Northern California this week spread throughout the state. Potentially heavy rain could start late Thursday in the southern part of the state.
The National Weather Service issued an advisory for minor flooding of roadways and low-lying areas in counties around San Francisco Bay and an avalanche warning was posted for eastern Sierra Nevada backcountry areas in Mono and Inyo counties.
Forecasters also issued a flood watch for areas east and southeast of Los Angeles starting Thursday evening because of possible heavy overnight rain fed by an atmospheric river, a long plume of moisture from the Pacific Ocean.
Evacuation warnings were issued by Orange County authorities for three canyons near a wildfire burn scar where rain last week unleashed muddy torrents. Warnings were also issued by San Bernardino County authorities for a half-dozen mountain areas.
Elsewhere, tire chains were required on several major routes through the Sierra Nevada and a stretch of coastal Highway 1 was closed south of Big Sur due to weather, according to the California Department of Transportation.
Periods of rain and snow were predicted for California through Christmas and into next week.
The Associated Press contributed to this report.
