He "knocked on doors, yelled and screamed" to alert as many residents as possible, Bernacett said.

"My husband tried his best to get everybody out. The whole hill's on fire. God help us!" she said before breaking down crying. She and her husband grabbed their dog, jumped in their pickup truck and drove through flames before getting to safety, she said.

Officials were sending as many firefighters as they could, Cal Fire spokesman Rick Carhart said.

"Every engine that we could put on the fire is on the fire right now, and more are coming," he said. "There are dozens of strike teams that we're bringing in from all parts of the state."

The sheriff confirmed reports that evacuees had to abandon their vehicles. He said rescuers were trying to put them in other vehicles.

"We're working very hard to get people out. The message I want to get out is if you can evacuate, you need to evacuate," Honea said.

The wildfire was reported around daybreak. Within six hours, it had grown to more than 26 square miles (69 square kilometers), Gaddie said.

"The blaze is being driven by fairly strong winds," Carhart said. "It's really dry and we have low humidity, and unfortunately those are great conditions for a fire to spread."

Thick grey smoke and ash filled the sky above Paradise and could be seen from miles away.

At the hospital with the stranded patients, some buildings caught fire and were damaged, but the main facility, Adventist Health Feather River Hospital, was not, spokeswoman Jill Kinney said.

Four hospital employees were briefly trapped in the basement and rescued by California Highway Patrol officers, Kinney said.

More than 40 patients were evacuated to other facilities. Twenty others were still awaiting rescue.

The National Weather Service issued red-flag warnings for fire dangers in many areas of the state, saying low humidity and strong winds were expected to continue through Friday evening.

AP