The Line Fire, about 60 miles east of LA, and two others have burned more than 100,000 acres combined.
Police in California have arrested a man on suspicion of starting the Line Fire - a major wildfire that has burned more than 34,000 acres (53 sq miles) in the state.
Justin Wayne Halstenberg, a 34-year-old resident of Norco, California, was stopped on Tuesday for arson and is being held in lieu of bail, officials said.
The Line Fire is one of three major wildfires sparked in the last week that are burning out of control in southern California, stretching firefighter resources and threatening thousands of homes.