PARADISE, Calif. (Reuters) - A fast-moving wildfire devastated a Northern California town of 26,000 people on Thursday with authorities unsure of the casualties as they struggled to contain 150-foot flames.

Driven by strong winds and dry conditions, the blaze dubbed the Camp Fire roared through the town of Paradise, about 85 miles (240 km) north of Sacramento, forcing the population to flee in a chaotic mass evacuation.

Fire ripped through residential areas and flames leapt from hospitals and schools, according to a Reuters witness, who saw a car dealership go up in flames on a street clogged with burned out vehicles and an abandoned police cruiser.

“The town is devastated, everything is destroyed,” said California Department of Forestry and Fire Protection (Cal Fire) spokesman Scott Maclean, who spent much of the day in Paradise. “There’s nothing much left standing.”

The town of Chico, population 93,000, could be next in the path of the wildfire, as flames were driven westward 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 fire was the fiercest of several wind-driven blazes across California on Thursday, during one of the state’s worst years for wildfires.

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“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 on Thursday and had charred 20,000 acres (8,093 hectares) by 8 p.m. (11.00 p.m. ET), said Cal Fire spokesman Rick Carhart.

Rescuers used a bulldozer to push abandoned cars out the way to reach Feather River Hospital and evacuate patients as flames engulfed the building, Butte County Supervisor Doug Teeter told reporters.

The hospital was totally destroyed, Mike Mangas, a spokesman for operator Dignity Health, told Action News Now.

Firefighting aircraft were unable to operate due to high winds, which were forecast to strengthen on Friday morning.

“The problem is the winds that pushed the fire so much, so fast,” said Maclean, adding that it could be days before authorities knew the full extent of fatalities and destruction.