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A 6,300-acre wildfire burning east of Silverwood Lake in the San Bernardino Mountains prompted new evacuations affecting more than 5,000 homes Monday.

The Pilot Fire tripled in size overnight, growing to 4,500 acres on Aug. 8, 2016. (Credit: KTLA)
The Pilot Fire tripled in size overnight, growing to 4,500 acres on Aug. 8, 2016. (Credit: KTLA)

The Pilot Fire started about 12:10 p.m. Sunday near the Miller Canyon OHV area off Highway 138, in the San Bernardino National Forest, according to the federal InciWeb page for the fire. The location is about 15 miles east of the Cajon Pass.

Fueled by dry brush and timber, the fire rapidly spread to 1,000 acres within hours. By Sunday night, it had grown to 1,500 acres before tripling in size during the overnight hours.

It was 6 percent contained as of Monday evening.

Mandatory evacuations were in place for Deer Lodge Park, Arrowhead Lake Road from Highway 173 to Ranchero Road, the San Bernardino County Sheriff’s Department said on Twitter.

Mandatory orders were also in place Monday afternoon for parts of Hesperia: Santa Fe Avenue east to Lake Arrowhead Road and everything south of Ranchero Road.

Voluntary evacuation orders affect the following areas, the Sheriff’s Department said:

  • North Lake Arrowhead; Brentwood east to Highway 173; everything north of the lake itself;
  • Golf Course Road east to North Bay Road, everything north of Peninsula to Highway 173;
  • West of Highway 173 and everything north of North Shore Drive across to Brentwood;
  • Aleutian Drive, Klondike Drive, Evergreen Drive and Yukon Drive.

Some 4,700 homes were affected in the mountains, with 500 homes in Hesperia evacuated.

Schools and offices in the Apple Valley Unified School District and in Hesperia will be closed Tuesday due to poor air quality from the fire.

The blaze is burning in a sparsely populated area that doesn’t have an extensive fire history. The vegetation is dense and hasn’t burned in years, creating challenging conditions for firefighters.

Firefighters arrive just after flames flare up along Highway 173 amid the Pilot Fire on Aug. 8, 2016. (Credit: KTLA)
Firefighters arrive just after flames flare up along Highway 173 amid the Pilot Fire on Aug. 8, 2016. (Credit: KTLA)

“Because the vegetation is so incredibly dry, all it takes is a little spark and it’s just been chewing through it,” Bob Poole of the U.S. Forest Service told the Los Angeles Times. “That’s been our difficulty.”

Fire officials fighting the blaze overhead used infrared mapping and determined that the fire had grown to 4,500 acres through the night.

“We still obviously have a very active wild fire,” Poole told KTLA in an interview Monday morning. He said the fire was moving north, toward Hesperia, but was still burning in a rural area.

The American Red Cross evacuation shelter was moved to Oak Hills High School, located at 7625 Cataba Rd., in Hesperia.

A second shelter was opened at Rim of the World High School, located at 27400 Highway 18 in Twin Peaks.

Large and small animals can be taken to the Victorville Fairgrounds, located at 14800 Seventh St. in Victorville.

Highway 173 between Highway 138 and Arrowhead Road remains closed, but Highway 138 is now open between the 15 Freeway and Highway 18, officials said.

Forest road closures included 2N33, 2N17X, 2N36 and 2N37, according to the Sheriff’s Department.

Eric Sherwin, a spokesman for the San Bernardino County Fire Department, said officials hope to increase the containment figures and get residents back to their homes.

Fire crews were focusing their early afternoon efforts on drawing containment lines around the wildfire, said County Fire Chief Mark Hartwig, noting there have been “a lot of flare-ups.”

“It really is, right now, about getting a containment line, and then protecting the structures that are in harm’s way,” he said.

Intense flames from the Pilot Fire shot up near power lines on Aug. 8, 2016. (Credit: KTLA)
Intense flames from the Pilot Fire shot up near power lines on Aug. 8, 2016. (Credit: KTLA)

Smoke advisories were issued for the Victor Valley and surrounding communities area and remain in effect Monday.

More than 843 firefighters are battling the blaze by ground and by air. Resources included 36 engines, eight crews, five dozers, eight helicopters and eight air tankers.

Warm, windy conditions are expected during the day, with area temperatures around the mid-70s and humidity at 19 percent, according to the National Weather Service.

Winds were coming out of the southwest at 15 mph, with gusts reaching speeds of 30 mph, according to Hartwig.

The cause of the fire remains under investigation.

KTLA’s Melissa Pamer contributed to this article.