How the Mountain Fire Began and Spread, as Officials Explain

Understanding the Origins of the Mountain Fire

Fierce winds and hot debris from an earlier tractor fire likely led to a blaze that burned 31 square miles and destroyed 243 structures in Ventura County last November, according to authorities. A year after the Mountain Fire, the Ventura County Fire Department released details of a months-long investigation, one that included hundreds of gigabytes of documents, thousands of pages of reports, photographs, and other evidence. Investigators found that the blaze started in the footprint of the smaller Balcom Fire a week earlier.

On Oct. 30, 2024, a tractor caught fire and flames spread into the brush near Balcom Canyon and Bixby roads in Somis. The fire burned an estimated 1.8 acres before it was declared out a few hours later. Firefighters used thermal imaging to scan for hot spots, dousing any they found.

For seven days, the fire-wrecked tractor sat in the middle of the burn area with no reports of smoke or other concerns, Fire Chief Dustin Gardner said. The closest brush was a couple hundred feet away, he said.

Then, investigators say it is more likely than not that debris buried underneath the tractor reignited in 70 mph winds. It had dislodged from underneath the tire of the tractor, spotted over the 200 feet of containment in place, and started the Mountain Fire, Gardner said.

On Nov. 6, 2024, dispatchers got a call about a fire growing fast near Balcom Canyon at 8:51 a.m. Forecasters had warned of extremely critical fire weather amid “particularly dangerous” Santa Ana winds.

The blaze quickly spread across the valley and through ranches and fields, spotting more than 2.5 miles ahead of itself as Santa Ana winds gusted, at times up to 80 mph.

In all, the fire that started near Somis damaged or destroyed 369 structures and threatened thousands more in communities from Camarillo to Fillmore. No deaths were reported.

While grateful for no fatalities, Gardner called the losses heartbreaking.

"The Mountain Fire was absolutely devastating to our community," he said, during a Nov. 7 news conference. "To everyone affected by the fire, you have our continued support and compassion."

The Initial Fire and Response

Shortly before 3 p.m. on Oct. 30, a caller reported seeing black smoke east of Balcom Canyon. Another caller said a tractor had caught fire on the hillside, according to the department's dispatch report.

A tractor operator had been clearing brush when he noticed smoke coming from the engine compartment, according to the Ventura County District Attorney's Office, which reviewed the fire investigation.

The department sent engines, hand crews, helicopters, and other aircraft to the fire burning in light winds, officials said. It was stopped at 1.8 acres.

Dozers carved a 12-foot-wide break around the fire, and a C-130 air tanker dropped fire retardant. Firefighters soaked a line around the perimeter, as others used hand tools to cut around it, the chief said.

They also walked shoulder to shoulder across the burn area and nearby grass and shrubs, looking for anything still smoldering, according to Gardner. Some used handheld thermal imaging devices to scan the ground. When they found a hot spot, they stopped, dug it up, and doused the area before moving on, he said.

By 6 p.m., the department declared the fire out. But the investigation continued.

Rekindling of the Balcom Fire

The next morning, department personnel flew a drone equipped with an infrared camera over the burn area, which showed two points of heat that glowed red on the screen.

One was near the dozer line and another around the tractor near the center of the burn area, the department said. Personnel dug out the hot spot near the containment line but described the heat at the tractor as something they would expect a day after the blaze.

The incident was then closed shortly before 11 a.m., and fire investigators notified the property owner they were done.

Over the next several days, the department said it received no reports of smoke or fire in the area. Investigators later interviewed several people at the site or nearby who reported no cause for concern in the days between the fires.

On Nov. 2, a little rain was recorded in the area. Then a few days later, the forecast called for an extreme Santa Ana wind storm. Investigators say the winds on Nov. 6 likely kicked up hot debris buried in or around a burned tire and blew it across the containment lines.

In 30 years, Gardner said he had never seen a similar situation in such vegetation after seven days.

Preventive Measures and Future Steps

What did officials do to stop such a fire? Based on firefighters' efforts – putting in multiple containment lines and dousing hot spots – crews didn't feel there was a threat of the fire spreading.

The department did not have a policy for continuing to monitor a fire after that work happens, though that could change.

Plans call for developing a program that would include flying drones over a burn area following brush fires. The department is still working to develop specifics such as how many days the monitoring would last. In the meantime, county fire will err on the side of "over reconning," according to the chief.

What such monitoring could have shown in the Balcom Fire is unclear. But while the points of heat at the tractor were expected the day after the fire, similar findings days later likely would have prompted further investigation, officials said.

Gardner said he believes the department did everything it could to suppress the Balcom Fire and exceeded industry standards. But the department will learn from this, he said.

He wants to work with other agencies and experts to try to find new technology or practices to put in place, he said.

"If we can find something to keep our community safer, then we will," Gardner said.

He also plans to have an independent, third-party review the department's operations on the Balcom Fire, he said. He will ask that team to look at every angle of the fire, the department's response, and say whether it could have or should have done something differently, he said.

Legal Implications and Ongoing Investigations

Will criminal charges be filed in the Mountain Fire? After the fire department's field investigation wrapped up, the California Department of Forestry and Fire Protection, which assisted in the probe, then reviewed the report.

Investigators said their work excluded various potential causes, including electrical lines. They considered a list of possibilities — among them, whether the earlier blaze could have reignited and reports of people shooting in the area days prior.

"It is not 100% sure," Gardner said of the final determination. "We're saying it's more likely than not the fire originated underneath that tractor seven days later."

In the spring, the records were forwarded to the Ventura County District Attorney's Office, which reviewed the investigative report to determine whether any charges would be filed. Officials said such scrutiny is not uncommon, particularly for large, damaging fires.

A team of senior prosecutors focused on the actions and the mindset of the tractor driver before, during, and after the Balcom Fire, District Attorney Erik Nasarenko said.

The driver, using a 2023 tractor with an attached shredder to clear dry vegetation and prepare the area for cattle grazing, was nearing completion on a 10-acre job, said Nasarenko, during the news conference.

When the driver noticed a fire starting near the engine, he immediately drove the tractor to an area he had already cleared, prosecutors said. He called for help and remained at the location.

"The evidence ultimately supported one conclusion – the tractor driver acted neither maliciously nor recklessly," Nasarenko said.

While the reason the tractor caught fire is unknown, there was no evidence that the driver drove it with the intention of starting a fire or operated the machinery aware one could occur, prosecutors said.

Authorities have said the deadly, destructive Palisades Fire in Los Angeles County in January also stemmed from an earlier blaze. The Lachman Fire ignited in brush in the Pacific Palisades area and then smoldered underground for a week, officials said. Heavy winds then stirred up the flames, causing them to spread above ground.