SAN FRANCISCO, California: A new round of extreme winter weather that hit California, also drifted into neighboring Southwest states, with authorities reporting five storm-related deaths in and around the San Francisco area due to falling trees.

Diana Crofts-Pelayo, spokesperson for the California Office of Emergency Services, said that due to the possibility of rain-swollen streams overflowing their banks or storm-weakened levees failing, some 48,000 people around the state have been warned to be prepared to flee to higher ground.

Most mandatory evacuation orders, which cover some 12,000 people, were in Tulare County in the San Joaquin Valley, where high water from recent levee failures has flooded many communities.

The storm was the twelfth in a recent succession of "atmospheric rivers," which have swept the West Coast since late December.

According to officials and local media reports, five people were killed this week by trees that fell due to high winds across California's Bay area, with two being in San Francisco and one each in Oakland, Contra Costa County and San Mateo County.

Two of the victims were reported to have died in their vehicles, and one was crushed inside a tent.

This winter, more than 20 other storm-related fatalities have been recorded across California during repeated episodes of violent weather.

The current wet winter has created an abrupt reversal of fortune for California, which has suffered for the past few years from drought and wildfires.