At least two people have died in California after melting snow in the rocky mountains and rain caused flash flooding and burst the levee of a river.
The coastal area of Monterey county was inundated after the Pajaro river overflowed, leading authorities to call for the area to be evacuated.
Millions of people across the state are on alert for flooding due to recent heavy rain, in addition to the rapidly melting snow.
Parts of the state have been hit by a weather phenomenon known as an atmospheric river, a large plume of warm water vapour that can stretch for hundreds of kilometres and cause prolonged rainfall.
“We were hoping to avoid and prevent this situation, but the worst case scenario has arrived with the Pajaro River overtopping and levee breaching at about midnight,” Luis Alejo, a Monterey County supervisor, said on Twitter.
Moses, a resident of the area for about 20 years, said: “Just the noise of the fire department — their sirens and all — woke us up.”
Officials later came and knocked on his door multiple times, but he decided to wait until 5am to make a decision.
After returning home from surveying the flooding, Moses, who preferred to give only his first name, said water was beginning to cover his street.
“That's when I told my wife, 'hey, we got to get out of here,'” he said.
The area remained under a flood warning on Saturday afternoon, the National Weather Service said.
On Friday night, state emergency services director Nancy Ward announced that the storm had already claimed at least two lives.
Images posted on Twitter by the state's National Guard account showed guardsmen rescuing residents trapped in cars by high water.
At least one road was washed away in Santa Cruz County, just north of Monterey. Soquel, also in Santa Cruz, was also badly flooded and CBS reported that about 9,000 people had been evacuated there.
Residents in several towns, mostly in the north, have been ordered to evacuate.
An unusually intense series of storms has battered California for weeks.
The latest storm was expected to dump as much as 23 centimetres of rain on already saturated ground.
Atmospheric river
Part of a powerful atmospheric river known as a “Pineapple express” — for the warm, subtropical moisture it brings from Hawaii — this latest storm will speed the melting of the enormous snowpack that has built up in higher elevations.
The resulting run-off threatens to aggravate already serious flooding.
In Pajaro on Saturday, the fire department and national guard used drones to survey the flooded areas, checking for people stranded in their homes, AFP reporters saw.
Two cousins, Angel Martinez and Christian Garcia, waded through the water carrying a plastic bag of food salvaged from the kitchen.
They told AFP their neighbourhood was a “wreck,” with water one-metre deep in their backyard.
They were only able to grab phone chargers, some blankets and a first aid kit when they hastily evacuated.
US President Joe Biden on Friday approved an emergency declaration that clears the way to expedite federal aid to the western state.
Mr Biden called Governor Gavin Newsom on Saturday to reaffirm full federal support for the impact of flooding and landslides on the state, a White House pool report said.
Mr Newsom said California was “deploying every tool we have to protect communities from the relentless and deadly storms battering our state.”
Storms in January were blamed for the loss of 20 lives.
