Lake and Ranch 2 fires burn thousands of acres as region is gripped in epic heat wave

Two brush fires in Southern California continued Saturday to burn thousands of acres, force hundreds of people from their homes and contribute to unhealthy air quality across the region.

The Lake fire, burning in the hills of the Angeles National Forest near Lake Hughes, had consumed 17,862 acres and was 12% contained as of Saturday night, authorities said. It had destroyed six buildings and continued to threaten thousands more, officials said.

Mandatory evacuations remained in place for Lake Hughes and the surrounding areas, though some evacuation orders that had been issued for the Antelope Valley were lifted Friday night. The American Red Cross was operating an evacuation point at Highland High School in Palmdale.

The fire was first reported Wednesday shortly before 3:40 p.m. There was no word on a cause.

The Ranch 2 fire, burning in the Angeles National Forest above Azusa, was at 1,400 acres and 3% contained as of Saturday morning, officials said.

The fire started about 2:45 p.m. Thursday in the San Gabriel River bed near San Gabriel Canyon and North Ranch roads, authorities said. Evacuation orders for Azusa’s Mountain Cove community were lifted Thursday night, but portions of Highway 39 remained shut.

Investigators were looking for a man believed to have started the fire. Police said the suspect, identified as 36-year-old Osmin Palencia, lived in an encampment in the riverbed near the blaze’s origin.

Firefighters were battling the fires amid a heat wave that forecasters said could rival the deadly seven-day heat event of July 2006.

The valleys, mountains and deserts of Southern California are likely to see daytime and nighttime temperature records challenged through at least Thursday, while humidity levels make conditions feel 2 to 5 degrees warmer during the day. Valley and inland areas are expected to see triple-digit temperatures for much of the week.

On Friday afternoon, the combination of heat and wildfires sent ozone pollution to levels not seen in a decade in some areas, according to the South Coast Air Quality Management District.

The air district said ozone, the invisible gas in smog that triggers asthma and other health problems, could reach “unhealthy� or “very unhealthy� levels in the afternoon hours from Saturday through Monday. The advisory covers areas including the Santa Clarita, San Fernando and San Gabriel valleys; the San Gabriel and San Bernardino mountains; the Inland Empire; and the Coachella Valley.

Times staff writers Paul Duginski and Tony Barboza contributed to this report.