A fast-moving wildfire roared through a Northern California town of US yesterday, with deaths reported as it burned a hospital, hundreds of homes and sent tens of thousands of people fleeing flames in cars and on foot, authorities said.

Driven by strong winds and dry conditions, the blaze dubbed the Camp Fire swept through the town of Paradise and threatened its 26,000 residents with 50-foot (15-meter) high flames.

The town of Chico, population 93,000, could be next in the path of the wildfire, which was forecast to be driven westward overnight by 35-mile-per hour (56 km-per-hour) winds, said Butte County Fire Chief Darren Read.

"We have received reports of some fatalities. Those reports have not yet been verified," Butte County Sheriff Kory Honea told a news conference.

The blaze adds to what is already one of the worst fire years ever in California. Flames have already destroyed 621,743 acres (251,610 hectares), nearly twice the amount during the same period of 2017 and nearly triple the five-year average.

"The whole town is burning," Bob Van Camp, a Paradise resident who escaped on his motorbike, told local TV channel Action News Now. "We had to ride through flames to get here," he said from the road between Paradise and Chico.

With the town located on a ridge and limited escape routes, traffic accidents turned roads into gridlock. Residents abandoned vehicles and ran from the flames carrying children and pets, officials said. One woman stuck in traffic went into labor, the Enterprise-Record newspaper reported.

"It's very chaotic. It's a very bad fire," Officer Ryan Lambert of the California Highway Patrol said of the evacuation.

The blaze began early yesterday and quickly charred 18,000 acres (3,237 hectares), forcing the evacuation of the 27,000 residents of Paradise, about 85 miles (240 km) north of Sacramento, California Fire said in a statement.

Authorities used a bulldozer to push abandoned cars out the way to reach Feather River Hospital and evacuate patients as flames engulfed its old wing and the roof of the emergency department, Butte County Supervisor Doug Teeter told reporters.

The hospital was later destroyed, Mike Mangas, a spokesman for operator Dignity Health, told Action News Now. The Paradise Immediate Care clinic was also destroyed, owner Brad Smith told the television station.