Officials said at least two outbuildings were also destroyed by the blaze, which began shortly before 5 p.m. Friday. No injuries have been reported.
Responding 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 retardant on Saturday to help establish containment lines and protect firefighters on the ground.
Firefighters began to gain the upper hand Sunday morning, containing some of the fast-moving blaze.
The cause of the fire is under investigation, but authorities say it likely may be a case of arson. Officials say the blaze may have started after two suspected arson fires merged into one on Friday.
"It's kinda scary. I mean, it's not scary but I'm angry," Banning resident Bryan Quan said. "Honestly I'm angry that somebody could intentionally light this. It burns me."
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 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.
Crews are expected to focus their efforts on the Banning Bluff area, said Captain Fernando Herrera of Cal Fire Riverside.
"The fire made a good run last night, threatened a lot of the homes," he said.
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An evacuation center has been established at Beaumont High School, 39139 Cherry Valley Blvd. 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.