CHERRY VALLEY, Calif. (KABC) -- The massive Apple Fire in Riverside County was started by a vehicle's mechanical malfunction, investigators have determined.
The fire has scorched more than 26,000 acres in Cherry Valley, destroying several buildings and triggering evacuations.
Investigators with CAL FIRE have determined the fire started Friday around 4:55 p.m. by a diesel-fueled vehicle driving around the 9000 block of Oak Glen Road in Cherry Valley. The vehicle emitted burning carbon from the exhaust system, which lit dry brush in the area, setting off a blaze which took off in hot, low-humidity conditions.
They asked anyone who was driving by that area at that time to come forward to speak with investigators. Calls can be made to the anonymous hotline at (800)633-2836.
Firefighters on Monday were continuing to battle the blaze, which Cal Fire said had burned 26,450 acres and was only 5% contained.
Officials said at least two outbuildings were also destroyed by the blaze, which began shortly before 5 p.m. Friday near Oak Glen Road and Apple Tree Lane. No injuries have been reported in the region's first major wildfire of the season.
Some 2,000 firefighters in the air and on the ground attacked the flames in an effort to protect the 2,500 homes that were threatened. Crews performed water drops from helicopters, dropping 19,000 gallons of flame retardant on Saturday to help establish containment lines and protect personnel on the ground.
"The helicopters were amazing -- and the planes also, dropping Phos-Chek," said Banning resident and evacuee Leah Westbrook. "It was fabulous, watching how well they could pour their water out right on the right spot, at the right time -- times when we were just going, 'Oh no, this is the end!' -- and they were hit exactly the right mark."
Cal Fire Capt. Fernando Herrera said planes and helicopters would continue supporting the firefight on Monday.
"Today we're going to bring in the same amount of aircraft that we had yesterday," including so-called VLATs, or very large air tankers, which can carry a payload of 10,000 gallons of fire retardant, Herrera said. "So they can spread that well ahead of the fire and hopefully slow it down."
Steep and rugged terrain made it difficult for crews on the ground to access the front lines. High temperatures and low humidity levels fueled the flames, which were scorching the brush that hadn't burned in years.
"Lots of oils in, so when it's going up these canyons, it's creating all that heat because of those oils and those fuels," said Cal Fire Capt. Richard Cordova. And what you'll see is these big plumes of smoke going up, especially the darker (ones), and once it gets into the atmosphere, it'll start creating its own weather."
An evacuation order was issued for the area north of Cherry Valley Boulevard, west of Highland Springs Avenue and east of Beaumont Avenue. An evacuation center was established at Beaumont High School, located at 39139 Cherry Valley Blvd. in Beaumont.
The evacuation orders were then expanded for homes north of Wilson Street, east of Sunset Avenue and west of Hathaway Street. The Oak Glen community in San Bernardino County was also placed under an evacuation order.
Voluntary evacuation orders were issued for residents in the Forest Falls area, but the order was later downgraded to an evacuation warning.
Residents in those areas, like Craig Parker, were hoping the fire wouldn't spread toward their homes.
"As long as the wind stays down, I don't think it'll go much further," said Kristy Gastelum. "They should be able to hopefully get a handle on it."
Nearly 2,600 homes, totaling some 7,800 people, were affected by the evacuation orders, fire officials said. Fire officials said they do not have a time frame for repopulating evacuated areas.
Anyone who goes to the evacuation center is subject to COVID-19 testing before entering, according to fire department spokesperson Fernando Herrera.
The American Red Cross was also assisting evacuees by temporarily housing them in hotels.
On Sunday night, the state Office of Emergency Services said FEMA has approved a request from the Cal OES director and Gov. Newsom for a Fire Management Assistance Grant for the Apple Fire. Officials said the approval "will ensure the availability of vital resources" for Riverside and San Bernardino counties.