PARADISE, Calif. -- A fierce wildfire in Northern California incinerated most of a town of about 30,000 people with flames that moved so fast there was nothing firefighters could do, authorities said Friday. Nine people died in what quickly grew into the state's most destructive fire in at least a century.

Only a day after it began, the blaze near the town of Paradise had grown to nearly 140 square miles (362 square kilometres), had destroyed more than 6,700 structures -- almost all of them homes -- and was burning completely out of control.

"There was really no firefight involved," Capt. Scott McLean of the California Department of Forestry and Fire Protection said, explaining that crews gave up attacking the flames and instead helped people get out alive. "These firefighters were in the rescue mode all day yesterday."

With fires also burning in Southern California , state officials put the total number of people forced from their homes at about 250,000. Evacuation orders included the entire city of Malibu, which is home to 13,000, among them some of Hollywood's biggest stars.

President Donald Trump issued an emergency declaration providing federal funds for Butte, Ventura and Los Angeles counties.

When Paradise was evacuated, the order set off a desperate exodus in which many motorists got stuck in gridlocked traffic and abandoned their vehicles to flee on foot. People reported seeing much of the community go up in flames, including homes, supermarkets, businesses, restaurants, schools and a retirement centre.

Rural areas fared little better. Many homes have propane tanks that were exploding amid the flames. "They were going off like bombs," said Karen Auday, who escaped to a nearby town.

McLean estimated that the lost buildings numbered in the thousands in Paradise, about 180 miles (290 kilometres) northeast of San Francisco.

"Pretty much the community of Paradise is destroyed. It's that kind of devastation," he said.

While the cause of the fire wasn't known, Pacific Gas & Electric Company told state regulators it experienced an outage on an electrical transmission line near Paradise about 15 minutes before the blaze broke out. The company said it later noticed damage to a transmission tower near the town. The utility's filing was first reported by KQED News.

The massive blaze spread north Friday, prompting officials to order the evacuation of Stirling City and Inskip, two communities north of Paradise along the Sierra Nevada foothills.

The wind-driven flames also spread to the west and reached Chico, a city of 90,000 people. Firefighters were able to stop the fire at the edge of the city, Cal Fire Cpt. Bill Murphy said.

There were no signs of life Friday on the road to Paradise except for the occasional bird chirp. A thick, yellow haze from the fire hung in the air and gave the appearance of twilight in the middle of the day.

Strong winds had blown the blackened needles on some evergreens straight to one side. A scorched car with its doors open sat on the shoulder.

At one burned-out house, flames still smouldered inside what appeared to be a weight room. The rubble included a pair of dumbbells with the rubber melted off and the skeletons of a metal pullup bar and other exercise equipment. The grass and elaborate landscaping all around the brick and stucco home remained an emerald green. Red pool umbrellas were furled near lounge chairs and showed not a singe on them.

Evacuees from Paradise sat in stunned silence Friday outside a Chico church where they took refuge the night before. They all had harrowing tales of a slow-motion escape from a fire so close they could feel the heat inside their vehicles as they sat stuck in a terrifying traffic jam.

When the order came to evacuate, it was like the entire town of 27,000 residents decided to leave at once, they said. Fire surrounded the evacuation route, and drivers panicked. Some crashed and others left their vehicles by the roadside.

"It was just a wall of fire on each side of us, and we could hardly see the road in front of us," police officer Mark Bass said.

Officials said all the victims were found in Paradise, including four who died inside their vehicles.

A nurse called Rita Miller on Thursday morning, telling her she had to get her disabled mother, who lives a few blocks away, and flee Paradise immediately. Miller jumped in her boyfriend's rickety pickup truck, which was low on gas and equipped with a bad transmission. She instantly found herself stuck in gridlock.

"I was frantic," she said. After an hour of no movement, she abandoned the truck and decided to try her luck on foot. While walking, a stranger in the traffic jam rolled down her window and asked Miller if she needed help. Miller at first scoffed at the notion of getting back in a vehicle. Then she reconsidered, thinking: "I'm really scared. This is terrifying. I can't breathe. I can't see, and maybe I should humble myself and get in this woman's car."

The stranger helped Miller pack up her mother and took them to safety in Chico. It took three hours to travel the 14 miles.

Concerned friends and family posted anxious messages on Twitter and other sites, saying they were looking for loved ones, particularly seniors who lived at retirement homes or alone.

About 20 of the same deputies who were helping to find and rescue people lost their own homes, Sheriff Kory Honea said.

"There are times when you have such rapid-moving fires ... no amount of planning is going to result in a perfect scenario, and that's what we had to deal with here," Honea told the Action News Network.

Kelly Lee called shelters looking for her husband's 93-year-old grandmother, Dorothy Herrera, who was last heard from Thursday morning. Herrera, who lives in Paradise with her 88-year-old husband, Lou, left a frantic voicemail around 9:30 a.m. saying they needed to get out.

"We never heard from them again," Lee said. "We're worried sick. ... They do have a car, but they both are older and can be confused at times."

For one desperate day, Dawn Johnson anxiously waited for news of her father Richard Wayne Wilson and his wife, Suzanne, who lived in an RV park in Paradise that burned. The couple moved from Texas to the California foothill town about a year ago and was probably not prepared for wildfires.

They lived in an RV park in the California foothill town and were unlikely equipped to evacuate. He has late-stage cancer and she is mostly confined to her bed, she said.

Johnson, of Independence, Oregon, relied on fellow members of the couple's Jehovah's Witnesses congregation to check local shelters. By Friday afternoon, she learned they had been found in nearby Chico.

"They are fine," she said.

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Associated Press writers Paul Elias in Paradise and Jocelyn Gecker, Janie Har, Daisy Nguyen, Olga R. Rodriguez, Sudhin Thanawala and Juliet Williams in San Francisco contributed to this report.

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This story has been amended to correct the last name of missing couple.