A wildfire that broke out in the inland mountains of Southern California has expanded exponentially, burning homes, forcing the evacuation of several small mountain communities and leaving three people injured.

About 1,500 people had evacuated as the wildfire of more than 9 square miles raged out of control in the San Jacinto Mountains near Banning, said Lucas Spelman, spokesman for the California Department of Forestry and Fire Protection.

Three were injured, including two firefighters taken to hospitals by ambulance and a burned civilian who was airlifted out, state fire officials said. They would give no further details on the injuries.

Fire officials said about a dozen structures were damaged or destroyed, but could not say how many were homes. Footage from TV news helicopters and photos from the scene showed several houses in flames.

They include the Twin Pines home of Dave Clark, whose parents were killed in a house fire in Riverside in April 2012 the Riverside Press-Enterprise reported. Prosecutors alleged Clark's sister Deborah Clark set the fire, and she was awaiting a mental-competency hearing to see if she was competent to stand trial for her parents' murder in a case that has received extensive local media coverage.

A photograph taken by the Desert Sun newspaper showed Clark talking on his cellphone with the home fully engulfed in flames behind him.

"He said he lost everything, he couldn't talk," brother Jeff Clark told the Press-Enterprise.

About 800 people evacuated the Silent Valley Club, a private RV resort, state fire spokesman Lucas Spelman said.

About 700 more were under evacuation order in the rural communities of Poppet Flats, Twin Pines, Edna Valley and Vista Grande, and evacuation centers were set up at high schools in Hemet and Banning. The communities are in the San Jacinto Mountains along Interstate 10 some 80 miles east of Los Angeles.

Margaret Runnels of Poppet Flats was at work when her house came under an evacuation order. She was in Banning waiting for her husband to collect pets and valuables from their house.

"I was hoping they would let me back up to get some personal items I knew my husband would forget like a jewelry box and stuff that means stuff," a crying Runnels told the Desert Sun. "You always tell yourself to prepare everything but you never take the stupid time to do it."

More than 500 firefighters, helped by five helicopters and five air tankers, were working to protect homes and get ahead of the flames. All but three helicopters were grounded after night fall but were set to return to the air Thursday morning.