The fires broke out on the second day of so-called red flag alerts triggered by the gusty Santa Anas, which flow offshore from the interior, driving down humidity and drying out vegetation. The National Weather Service said the cause of the winds, surface high pressure in the Great Basin, was expected to persist through early Friday.
The fire near the Marine Corps' Camp Pendleton was reported about 4:30 p.m. and grew to about 40 acres within an hour, said Chief Tom Gardner of the California Department of Forestry.
In the earlier incident, a structure was destroyed in a six-acre blaze at Malibu Creek State Park in the Santa Monica Mountains west of Los Angeles.
Some 200 firefighters aided by two water-dropping SuperScooper planes and three helicopters controlled the fire in about an hour, said Los Angeles County fire Inspector John Mancha.
No injuries were reported, and the cause was under investigation, authorities said.
