LOS ANGELES -- Authorities in California estimate that more than half of those forced to evacuate because of a wildfire in Malibu have been allowed to return home.

Officials say firefighters appear to be making progress on the blaze, thanks partly because the Santa Ana winds driving the fire have slowed.

Nearly 50 homes have been destroyed. All were damaged in the fire's initial morning surge.

Up to 14,000 people had to be evacuated because of the blaze, which was estimated this afternoon at 4,500 acres.

Officials say the blaze is now 25 percent contained but said containment numbers will more than double by Sunday.

Investigators are trying to determine the cause.

Hundreds of firefighters battled a rapidly spreading wildfire burning through the canyons and hills above Malibu, Calif.

Officials said the blaze began shortly before 3:30 a.m. PST in an area near Malibu Lake and was burning downhill.

Malibu Mayor Jeff Jennings praised the response of fire officials and said the silver lining was that only one injury had been reported as of Saturday morning.

"Waking up at 4 in the morning with smoke in your nose and the wind banging at the window is something you learn to live with here," Jennings said. "But it's still a shocker."

An evacuation center was set up at a local high school.

Helicopters and airplanes have been attacking the fire from the air, while 1,700 firefighters battle the flames on the ground.

The helicopters have lowered hoses into pools and the nearby Pacific to refill their tanks for water-dropping runs. Amphibious SuperScooper planes are skimming the ocean to reload.

Capt. Mike Brown with the Los Angeles County Fire Department said the fire is fast moving and there is a lot of dry vegetation in the area to fuel the fire.

A spokesman for Cal Fire, the top firefighting agency in the state, said at least 35 homes had been burned. The only injury reported as of Saturday morning was a minor injury to a state firefighter, the spokesman said.

The cause of the fire is still under investigation.

Officials at Pepperdine University told their students to move to a campus shelter as a precaution. However, the university was largely empty because of the holiday weekend.

"Prior to the Thanksgiving holiday I was told the weather conditions was Santa Ana winds and we all know what that means," said university spokesman Jerry Derloshon.

Forecasters said the seasonal winds could gust as high as 75 mph up until Saturday night. Humidity levels are also low.

Red flag warnings have been issued for a wide area including parts of Ventura, Los Angeles, Riverside, Orange and San Diego counties. And advisories are posted up the coast for areas expected to have lower winds.

The National Weather Service said the latest Santa Ana winds are less severe than the ones that gusted as high as 100 mph and fanned devastating wildfires across the region in October.

Another fire broke out Saturday morning in San Diego County near the town of Ramona. It burned dozens of acres, but was 40 percent contained by Saturday afternoon.