MALIBU, Calif. — More than 3,700 residents were allowed to return to their Malibu homes on Thursday after calmer winds and rising humidity in Southern California helped firefighters battle a blaze that had forced thousands, including college students and celebrities, to evacuate earlier this week.

But another 1,600 people with homes in Malibu — a city typically known for its rugged canyons, stunning bluffs and celebrities’ seaside mansions — remained under evacuation orders. All told, some 20,000 residents in the city and neighboring areas had been affected by mandatory evacuation orders and warnings since the fire broke out late Monday.

Firefighters continued to battle the blaze, dubbed the Franklin Fire, which was only 20% contained over about 6.3 square miles (16.3 square kilometers) Thursday. The flames were fed by powerful winds that swept through the region in the beginning of the week. But the weather improved so much Wednesday that meteorologists discontinued all red flag warnings, which indicate high fire danger, and fire crews were able to successfully push back against the flames.

Winds would continue to ease, said meteorologist Mike Wofford with the National Weather Service’s office for Los Angeles.

“We’ll even get a little sea breeze there that will increase humidity in the fire zone,” Wofford said Thursday. “Generally everything’s getting better.”

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How the Fire Started Is Still Under Investigation

It’s unclear how the fire started. Officials said four homes have been destroyed and at least six others have been damaged, though crews had only surveyed about 25% of the affected area, said Deputy Chief Eleni Pappas of the Los Angeles County Fire Department.

“This is a tragedy that goes beyond our personal residences,” Malibu Mayor Doug Stewart said, adding that restaurants have lost food in their freezers from power outages and people who travel to Malibu for employment are out of work.

The 3,700 residents were allowed to return Thursday after the county sheriff’s department lifted mandatory evacuation orders.

Flames also reached just short of Pepperdine University, where students were forced to shelter in place on campus on Monday and again Tuesday.

An early analysis showed little to no damage to structures on campus, the university said. Final exams were postponed or canceled and faculty members were determining how best to complete the semester, which ends at Pepperdine this week.

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Lonnie Vidaurri’s four-bedroom home in the Malibu Knolls neighborhood was one of those impacted. He evacuated to a hotel in Santa Monica with his wife and two young daughters.

“It’s pretty torched all around,” Vidaurri said of his house. He expects that the family’s pet bunnies did not survive the fire, and that they lost most of their things. “My girls cried, obviously, but it could have been worse.”

Mimi Teller, a Red Cross spokesperson who works at a shelter in nearby Pacific Palisades, said many evacuees arrived in pajamas and were “definitely in shock.”

“Nobody even had a backpack, it was, ‘Get out now,’” Teller said.

Celebrities Forced to Flee

Cher, one of many celebrities with homes in Malibu, evacuated from her home when ordered and was staying at a hotel, her publicist, Liz Rosenberg, said Tuesday. Jane Seymour also fled the seaside city. “The fires in our community are a stark reminder of how quickly life can change,” the actress wrote on Instagram Tuesday.

And Dick Van Dyke said in a Facebook post that he and his wife, Arlene Silver, evacuated as the fire swept in. The actor later told NBC’s “Today” that neighbors helped them get out.

“I was trying to crawl to the car. I had exhausted myself. I couldn’t get up,” said Van Dyke, who turns 99 on Friday. “And three neighbors came and carried me out, and came back and put out a little fire in the guesthouse and saved me.”

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The fire erupted shortly before 11 p.m. Monday and swiftly moved south, jumping over the famous Pacific Coast Highway and extending all the way to the ocean. It was propelled by Santa Ana winds, with erratic gusts that topped 40 mph (64 kph). Santa Anas are notorious seasonal winds that blow dry air from the interior toward the coast, pushing back moist ocean breezes.

Utilities preemptively shut off power to tens of thousands of homes and businesses, starting Monday night, to mitigate the impacts of the Santa Anas, which can damage electrical equipment and spark wildfires. As of Thursday morning, electricity had been restored for all Southern California Edison customers, said utility spokesperson Gabriela Ornelas.

The Woolsey Fire that roared through the area in 2018, killing three people and destroying 1,600 homes, was sparked by Edison equipment. Asked Thursday if Edison equipment was involved in the Franklin Fire, Ornelas referred all questions regarding the cause to fire officials.