BONSALL, Calif. (CBSLA/AP) — Officials have ordered mandatory evacuations due to a fast-moving fire fanned by Santa Ana winds that is burning in the Bonsall area of northern San Diego County.

The Lilac Fire near Old Highway 395 and Dulin Road had grown to 4,100 acres as of 8 p.m. There was no containment. The fire was reported about 11 a.m.

CAL Fire said that three civilians had sustained burn injuries and one civilian had been injured due to smoke inhalation. Two firefighters sustained minor injuries.

Authorities said that the fire destroyed 20 structures and left 12 damaged.

Nearly 20,000 SDG&E customers were without power Thursday afternoon.

San Diego Fire-Rescue and Marine Corps Base Camp Pendleton were sending water-dropping helicopters to assist in the firefight.

The following areas are under an evacuation warning: South of North River Road, North of Oceanside Boulevard, West of Melrose and North Santa Fe, East of Old Grove Road and Douglas Drive.

The following areas are under a mandatory evacuation order: South of Camp Pendleton Eastern Fence Line, North of North River Road, West of Wilshire Road, East of Douglas Drive, South of North River Road, North of Bobier Drive, East of Melrose and North Santa Fe, West of East Vista Way, South of Reche Road, North of Burma Road, East of Camp Pendleton Eastern Fence Line, West of Green Canyon Road.

The evacuations include a mobile home park, a golf course country club and two schools.

Flames reached the San Luis Rey Downs training center. A large number of race horses are housed at this location.  A trainer told the local CBS station that as many as 15 horses may have perished. Witnesses said several horses were seen running wild near the property.

Temporary shelters have been set up at Fallbrook High School, the East Valley Community Center in Escondido, Pechanga Casino and Pala Casino, according to CAL Fire. Additional shelters are located at Oceanside High School and Stagecoach Community Center in Carlsbad.

Bonsall is located about 16 miles east of Oceanside.