A brush fire in the Angeles National Forest north of Azusa has grown to more than 300 acres and prompted the evacuation of hundreds of campers and hikers, officials said Sunday.
The fire started about 2:30 p.m. Sunday and grew quickly, officials said. High temperatures, low humidity and steep terrain made it difficult for firefighters battling the blaze.
The fire was at Mile Marker 24 on Highway 39, which had to be closed, according to a U.S. Forest Service spokesman. Residents were also not being allowed into the area, although no homes were threatened, authorities said.
Several water-dropping helicopters were assisting CalFire and Los Angeles County firefighters.
As of Sunday evening, there was no containment and the cause of the fire was unknown.