CAMPO  (AP) — A wildfire fanned by strong winds that prompted the evacuation of 150 homes in eastern San Diego County is 30 percent contained, officials said Monday.

But authorities with California's Department of Forestry and Fire Protection warned that the 907-acre blaze east of Campo still threatens 200 houses, sheds and other buildings.

Nearly 500 firefighters have been dispatched to attack fire, which has forced a mix of mandatory and voluntary evacuations and destroyed at least one home.

Water-dropping helicopters doused the area Monday, and firefighters braced for temperatures to rise and winds to pick up speed. A red-flag warning signaling prime wildfire conditions was scheduled to take effect at noon.

"As we get close to triple digits, we're going to probably see a lot more active spots," said Daniel Berlant, a spokesman for the state Department of Forestry and Fire Protection. "We still have quite a bit of work ahead of us here."

Still, fire officials expect the blaze to be fully contained Tuesday night.

The wildfire began at about 2 p.m. Sunday near the Golden Acorn Casino and sent flames burning along Old Highway 80. An evacuation center was set up at the casino.

Authorities evacuated 150 homes overnight. Evacuation orders were later made voluntary, but that could change if the weather shifts during the afternoon, said Arlene Fletcher, a supervisor with the San Diego County sheriff's communications center.

Fanned by winds, the fire nearly doubled in size overnight, and continued to grow Monday morning.

Berlant said the fire has burned one home and one other structure. But resident Mary Kanel told U-T San Diego that she watched from the casino parking lot as both her mobile home and her mother's mobile home went up in flames. The two residences were on the same property, across from the casino.

"We didn't get to grab" anything, a tearful Kanel told the newspaper. "We put three dogs and two cats in the cars. That was it. We had to go."

The red-flag warning remains in effect until 6 p.m. Tuesday, said James Thomas, a meteorologist at the National Weather Service for the San Diego region. The area can expect to see winds between 10 and 15 mph and gusts up to twice that in the afternoon, he said.

The cause of the fire is under investigation.

Meanwhile, a 300-acre fire near Cabazon prompted the evacuation of 15 families overnight. The evacuation orders were lifted Monday and the fire was 40 percent contained, Riverside County fire officials said.

A 2,200-acre wildfire that erupted Saturday in a remote area of the county was 70 percent contained Sunday night.