ANGELES NATIONAL FOREST — Firefighters continued getting the upper hand on the Williams Fire overnight and early Friday, and authorities early Friday announced containment lines had been built around 72 percent of the wildfire.
The blaze, which ignited Monday near Camp Williams in the Angeles National Forest north of Glendora, had scorched 4,180 acres but damaged no structures, according to the U.S. Forest Service.
The nearly 1,1000 firefighters working the blaze were largely transitioning from active firefighting operations to “mop-up” activities, such as hunting for and extinguishing hot spots and beginning the process of forest rehabilitation, USFS Fire Information Officer Robert Brady said.
“Yesterday, the fire it was looking good,” he said. “There’s was no appreciable smoke coming out, and good progress was made.”
An air tanker and 10 water-dropping helicopters continued soaking the fire from the air, officials said.
The 28 percent of the fire’s perimeter that remained unchecked was at it’s northwest edge, up against and encroaching into the treacherous terrain of the Sheep Mountain Wilderness Area, Brady said.
“It sounds like (Friday), they’re going to make use of that air support in the northeast areas,” he said. “They’re just holding that northeast corner, and the mop-up is a heavy priority.”
Firefighters were working on slopes of between 30 percent 80 percent, USFS officials said in a written statement.
“The remaining open line is on extremely steep and dangerous topography which makes line construction slow and role out of rocks and boulders a constant concern,” according to the statement.
Additionally, “There’s a lot of rehab work starting,” Brady said.
The process starts with firefighters removing all trash, scorched hoses, broken tools and other items they brought into the forest with them for the firefighting effort, Brady said.
Officials then move on to to other measures, such as creating “water bars” to help prevent excessive erosion and taking steps to help the area irrigate itself as it would before the vegetation was burned away to foster quick re-growth.
The forest remained off-limits for the public Friday and Highway 39 remained closed in the forest, though several-dozen permanent residents of Camp Williams were allowed to return home with a sheriff’s escort Thursday morning.
Winds of about 5 mph pushed the fire toward the east, USFS officials said.
A relative humidity of 40 percent favored firefighting in the morning, Brady said, however afternoon temperatures were expected to climb above 90 degrees.
Full containment was expected Thursday.