Orange County firefighters Friday were battling a 50- to 70-acre brusher in San Clemente.
The fire in the area of Portico Del Norte broke out about 11:30 a.m., according to the Orange County Fire Authority.
Reports from the scene indicate some structures may be threatened off Via Entrada and the blaze was being driven by wind and terrain.
There were no immediate reports of injuries, and the cause of the fire was unknown.
Crews were battling the fire on the ground and with the assistance of water-dropping aircraft.