Thousands of homes remained evacuated Sunday as two massive wildfires raged in tinder-dry California hills and canyons, and authorities said a burned body was found in one neighborhood swept by the flames, AP reported. The body was discovered Saturday evening outside a home on Iron Canyon Road in Santa Clarita, just north of Los Angeles, and detectives are trying to determine whether the person was killed by the blaze or another cause, Los Angeles County sheriff's Lt. Rob Hahnlein said. The home also may have burned, he said. The area was among those ordered evacuated as the fire raged through brush withered by days of 100-degree temperatures as Southern California sweltered through a heat wave. Since Friday, the fire, propelled by gusty winds, has burned up and down ridgelines, blackening 31 square miles of brush on the edge of Santa Clarita and the Angeles National Forest. It was 10 percent contained late Saturday night. After flames swept through an evacuated neighborhood, firefighters reported that some buildings had been engulfed, but it was not immediately clear whether they were homes, outbuildings or garages, said Nathan Judy, a spokesman for the U.S. Fire Service. The area was still unsafe, he said late Saturday night. "You've still got hotspots in that area, a lot of smoldering stuff," and trees that might fall because their roots had burned, Judy said. Smoke and ash from the fire cast a pall over neighboring Los Angeles. Air quality officials advised people with respiratory problems to stay indoors.