ANAHEIM, California — A wildfire burning among houses in the hills southeast of Los Angeles was ignited by flames from a stolen car that was intentionally set ablaze during strong winds, a fire official said yesterday.Orange County Fire Authority Battalion Chief Ed Fleming stopped short of calling it arson, however, because it was not clear if the intent was to start a wildfire or simply cover up criminal evidence.

“They have confirmed that it was a stolen car and that the car was intentionally ignited,” Fleming said. “As we fight the fire, they are trying to come up with every lead possible to figure out who did this and why and what their motive was.”

The three-square-mile blaze had damaged two homes but was 80 percent contained by midmorning, up from just 30 percent early in the day, fire officials reported.

At daybreak yesterday, the temperature was still in the upper 50s, compared to Sunday’s highs near 100. “The weather is co-operating at this point,” Orange County Fire Capt. Ian MacDonald said.

Dry, windy weather remained a concern for the rest of the day, though, said Orange County Battalion Chief Ed Fleming. The National Weather Service forecast temperatures in the 80s and 90s.

“It is going to cause some challenges for the firefighters, but they are going to work through the day and through the night to make sure it is contained by tomorrow,” Fleming said.

A red flag alert, indicating high fire danger, remained in effect in much of Southern California, where a prolonged drought has made the chaparral-covered hills highly combustible.

“In Southern California, we’re always 24 hours away from having a wind-driven, low humidity fire,” MacDonald said.

The wildfire was reported Sunday morning, and hot, dry wind quickly spread it through an unincorporated part of Orange County, threatening multimillion-dollar homes in Anaheim and in Anaheim Hills, about 35 miles southeast of Los Angeles.

Residents of about 500 homes were evacuated but most were able to return Sunday night. Two homes and another structure were damaged, and a fourth structure was destroyed, said Capt. Steve Miller of the Orange County Fire Authority.

Authorities said the blaze may have been started by a vehicle fire. They were investigating if the car was stolen and set on fire to destroy evidence.

The dry we ather comes two years after the region was awash with a near-record 37 inches of rain. Only about 2.4 inches of rain has fallen on downtown Los Angeles since July 1. Normal annual rainfall in Los Angeles is 11.43 inches.

The National Oceanic and Atmospheric Administration’s weather models suggest that an emerging La Nina pattern of cold water in the tropical Pacific will keep the area dry.