Fire burning in Los Angeles' San Gabriel Mountains proves tough to contain.
Firefighters are preparing early Tuesday for another attack on a 3,600-acre wildfire that started Sunday in Angeles National Forest in southern California and prompted the evacuation of a popular camping area during Labor Day weekend.
The Williams fire, which started in the Camp Williams park along East Fork Road off Highway 39, might not be contained until next week, according to fire officials.
Firefighters are facing steep terrain with dry brush that has not burned for 15 to 20 years.
"We have some challenges we face out there," said Inspector Tony Imbrenda, of the Los Angeles County Fire Department. "We expect that this is going to take several days to get some containment."
About 800 firefighters and 21 firefighting aircraft were assigned to the fire.
Crews are protecting structures in the Camp Williams area.
Wind gusts reached 25 mph Monday night after a day of temperatures in the mid-90s and low humidity levels.
The acreage figure was revised Monday from 4,000 to 3,600 acres after crews obtained updated mapping.
Containment was a 15 percent early Tuesday.
There are no residential areas in the path of the fire, which is moving north.
The cause of the fire remains under investigation.