An explosive wildfire destroyed about 70 homes in the ritzy community of Montecito, injured four people and forced thousands to flee wind-whipped flames in the longtime hideaway for celebrities such as Oprah Winfrey and Rob Lowe.

The fire started around 6 p.m. Thursday and quickly spread to about 800 acres — more than a square mile — destroying dozens of homes in less than five hours in the foothills of Montecito, just southeast of Santa Barbara. Several fire departments were battling the flames as thick plumes of smoke hovered overhead.

"It looked like lava coming down a volcano," Leslie Hollis Lopez said as she gathered belongings from her house.

Montecito fire spokeswoman Geri Ventura said about a quarter of the community of 10,000 people was evacuated and more could be moved out if the fire spreads.

Students at Westmont College holed up in the school's gym as flames burned a dormitory and several buildings containing classrooms. The college said on its Web site it was considering moving the students to a Red Cross shelter if they can get safely through the fire.

The injuries included two people who suffered smoke inhalation and two others taken to Santa Barbara Cottage Hospital with substantial burns, said Janet O'Neil, the hospital's director of public affairs.

Thousands of feet above the flames, footage shot from television helicopters showed what initially looked like a massive campfire with dozens of glowing embers. When cameras zoomed in, however, what appeared to be flaring coals were actually houses gutted by flame. Many of the homes were sprawling estates.

"You can just hear the explosions ... of vehicles, homes," Michaelo Rosso told KCAL- TV as he prepared to leave his home. "It sounds like the Fourth of July out here."

About 125 engines and three water-dropping helicopters were en route or at the scene, said Xenia Tihomirova, a spokeswoman for Santa Barbara County.

Firefighters faced wind gusts as high as 70 mph Thursday night. Gusts were expected to remain strong through early Friday, according to the National Weather Service in Oxnard. The fierce winds known locally as "sundowners" blow from land to sea in the evening, reversing the normal onshore flow of cool, moist sea breezes. They are caused by the area's unique topography.

The fire temporarily knocked out power to more than 20,000 homes in Santa Barbara, said Southern California Edison spokesman Paul Klein. He said only scattered pockets of homes were without power by late Thursday.

Montecito and its multimillion-dollar homes with ocean views have long attracted celebrities such as Michael Douglas, Lowe and Winfrey, who owns a 42-acre estate there. The landmark Montecito Inn was built in the 1920s by Charlie Chaplin and Fatty Arbuckle, and the nearby San Ysidro Ranch was the honeymoon site of John F. Kennedy in 1953.

Publicists for Lowe and Winfrey told the AP the celebrities' homes had not been destroyed and that neither was staying in the area Thursday night.

Montecito suffered a major fire in 1977, when more than 200 homes burned. A fire in 1964 burned about 67,000 acres — nearly 105 square miles — and damaged 150 houses and buildings.