Firefighters were on high alert Tuesday as winds gusting up to 50 mph threatened to flare up hot spots from three Southern California wildfires.

The winds and forecasts of low humidity prompted the National Weather Service (search) to issue a red flag warning until Wednesday afternoon. The warning advises that conditions could lead to explosive fire growth.

The region's largest blaze, at more than 24,000 acres on the border of Los Angeles and Ventura counties, was fully contained, officials with the California Department of Forestry and Fire Protection (search) said. The blaze destroyed three homes.

Inspector Ron Haralson of the Los Angeles County Fire Department (search) said he was worried about the weather forecast.

"You have to have a watchful eye over the whole area right now," he said.

Firefighters surrounded a 1,100-acre fire in rugged terrain in the hills above Burbank, said Capt. Ron Bell of the Burbank Fire Department. Crews remained on the scene to tamp down hot spots from the blaze that started Thursday.

In San Bernardino County, a 935-acre fire was 85 percent contained, said Carol Beckley, spokeswoman for the U.S. Forest Service.

The fire was burning in steep, rugged terrain in and around San Bernardino National Forest (search), about 70 miles east of Los Angeles.