Apple Fire in California was sparked by vehicle malfunction, blaze scorches 41 square miles

Thousands have been evacuated in Riverside and San Bernardino Counties due to the blaze

A wildfire that's burning in the mountains east of Los Angeles and forced thousands of people from their homes was sparked by a malfunctioning vehicle, officials revealed on Monday.

CAL Fire said the Apple Fire was ignited by a vehicle that "appeared to have mechanical problems" and was traveling along Oak Glen Road in Cherry Valley, Calif., just before 5 p.m. Friday.

"Specifically, a diesel-fueled vehicle emitting burning carbon from the exhaust system," the agency said. "The determination is reinforced by multiple independent witnesses, as well as supporting physical evidence."

APPLE FIRE IN CALIFORNIA SENDING 'LARGE AREA OF SMOKE' TO PHOENIX, HUNDREDS OF MILES AWAY

The fire has destroyed at least four homes and two outbuildings while threatening dozens more, fire officials said.

As of Tuesday morning, the fire is 15 percent contained and has consumed some 41 square miles of dry brush and chaparral in Riverside County.

Firefighters watch the Apple Fire in Banning, Calif., Sunday, Aug. 2, 2020.

Firefighters watch the Apple Fire in Banning, Calif., Sunday, Aug. 2, 2020. (AP Photo/Ringo H.W. Chiu)

An emergency closure order was put in place Sunday prohibiting all entry into the San Gorgonio Wilderness Area, including the Pacific Crest Hiking Trail between the forest boundary and Forest Road 1N01, according to FOX11.

Hand crews work on the remaining hot spots from a brush fire at the Apple Fire in Cherry Valley, Calif., Saturday, Aug. 1, 2020.

Hand crews work on the remaining hot spots from a brush fire at the Apple Fire in Cherry Valley, Calif., Saturday, Aug. 1, 2020. (AP Photo/Ringo H.W. Chiu)

Several evacuations are in place in both Riverside and San Bernardino counties, impacting thousands of residents. At one point, sweeping orders impacted some 8,000 people.

John Medina, an American Red Cross spokesman, said that coronavirus precautions made for added stress at an evacuation center.

Volunteers used to "close contact” with evacuees have had to adjust their approach during a time of social distancing, Medina said.

“I mean, that’s part of the recovery of a disaster, is that you have to show warmth and love and caring. And that’s hard when you’re standing six feet away. So that’s the biggest challenge,” Medina told KESQ-TV.

APPLE FIRE IN CALIFORNIA EXPLODES TO MORE THAN 32 SQUARE MILES, THOUSANDS EVACUATED

The wildfire has generated a smoke plume that was visible for miles around and contributed to poor air quality.

Smoke from the Apple Fire can be seen in this satellite image from NASA.

Smoke from the Apple Fire can be seen in this satellite image from NASA. (NASA/GOES-East)

Smoke from the wildfire has drifted over western Arizona and the Phoenix area.

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Officials allowed flames from the Apple Fire to run up the side of Mount San Gorgonio, an 11,000-foot peak, because it wasn't safe to let crews work in such steep, rugged terrain, according to Lisa Cox, a spokeswoman for the U.S. Forest Service.

A firefighter watches as a helicopter drops water onto the Apple Fire near Banning, Calif., Sunday, Aug. 2, 2020.

A firefighter watches as a helicopter drops water onto the Apple Fire near Banning, Calif., Sunday, Aug. 2, 2020. (AP Photo/Ringo H.W. Chiu)

Firefighters battling the blaze have faced "dangerously hot conditions” that are expected to continue. Fire danger remains high on Tuesday for parts of the West.

Temperatures continue to soar over the Southwest with another day of excessive heat warnings.

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The Southern High plains could also set records with daytime highs reaching over 100 degrees.  
 
Fox News' Janice Dean and the Associated Press contributed to this report.