Firefighters have set controlled fires to help clear vegetation around the 32,412-acre Apple Fire burning along slopes in the San Bernardino National Forest, and planned to fly personnel into a remote area of the San Gorgonio Wilderness Saturday to clear lines of vegetation.

It was described as a “firing operation,” and involved firefighters using flames to clear three miles of fire line on the eastern edge of the fire, putting up a lot smoke that dissipated as the vegetation was consumed, officials said.

Main fire progression was expected to continue to the northeast into the wilderness, with warmer and drier weather conditions expected over the next few days. Temperatures were forecast to be 85 to 95 degrees with decreasing humidity over the fire area.

The San Gorgonio Wilderness area remained closed.

Firefighters also planned to continue work on the Yucaipa Ridge to improve the perimeter line with the number of units handling structure protection in Oak Glen and Forest Falls reduced as the lines become more secure.

The fire was 35 percent contained by Saturday morning, with 2,845 firefighters assigned, and it was estimated the fire will be fully contained by Aug. 17.

More than a week after the blaze was started July 31 by the malfunctioning exhaust system of a diesel vehicle, four homes and eight outbuildings had been destroyed. A firefighter sustained a head injury when he was struck by a falling tree branch on Thursday and taken to a hospital. No other details were available, including his identity or condition.

An estimated 2,600 residences and 7,800 people were evacuated at the height of the fire. All evacuation orders in Riverside County have since been lifted.

Shortly before noon Friday, the U.S. Forest Service canceled an order that had been in place for the Oak Glen area just north of the boundary separating San Bernardino and Riverside counties, including Potato Canyon and Pine Bench. That was the last of the mandatory evacuation directives.

In San Bernardino County, non-mandatory evacuation warnings remained for Forest Falls, Morongo Valley, Rimrock and Pioneertown, according to the USFS.

The Whitewater Canyon community north of Interstate 10 and west of Highway 62 in Riverside and San Bernardino counties was added to the voluntary evacuation warning list Thursday.

“Good progress has been made on Yucaipa Ridge, as well reducing the threat to Forest Falls,” according to a USFS statement. “As threats are reduced and the containment line has been completed, firefighting resources will shift to areas of greater threat as needed.”

The head of the fire is on a mountainside in San Bernardino County, where the vast majority of the firefighters assigned to the fire are working. A total of 20 aircraft — 18 water-dropping helicopters and two air tankers — have been rotating in and out of the fire zone, helping lay down tentative containment boundaries.

Along with county fire crews, personnel from the Calimesa, Morongo, Murrieta, Palm Springs, Cathedral City, Huntington Beach, Hemet, Pechanga, San Bernardino, Soboba, Los Angeles and Los Angeles County fire departments were sent to assist.

Residents with questions or concerns about the fire can call 909-383-5688.

>> Want to read more stories like this? Get our Free Daily Newsletters Here!