THOUSAND OAKS — Arson investigators determined the likely cause of the Mountain Fire was extreme wind dislodging a pocket of covered, hot tire debris from an earlier fire, the Ventura County Fire Department announced Nov. 7.
“The Mountain Fire was devastating to our community,” Fire Chief Dustin Gardner said. “To everyone affected by the fire, you have our continuing support. Neighbors to all of us here in Ventura County lost homes and possessions, including irreplaceable photos and keepsakes. Others were forced to flee, not knowing whether they would have homes to come back to. It was heartbreaking and the emotional scars of this fire will last long after the homes are rebuilt.”
“I also want to thank all the first responders who worked so hard for so many days to fight this fire,” Gardner said. “As terrible as the Mountain Fire was, it only destroyed property. It did not claim any lives. Your efforts were a big reason. Now we have an opportunity to look at the cause of this fire and learn from it.”
The Mountain Fire, which started Nov. 6, 2024 burned nearly 20,000 acres and damaged or destroyed 369 structures.
Investigators from the Ventura County Fire Department and the California Department of Forestry and Fire Protection (CALFIRE), conducted an extensive review of the fire, producing 360 gigabytes of data, 2,800 electronic files and several thousand pages of reports.
They found that the origin of the Mountain Fire was a tractor fire that occurred Oct. 30, 2024, during brush clearing work near Balcom Canyon Road and Bixby Road in the community of Somis. The tractor operator saw smoke and fire coming from the engine, drove the tractor to an area he had cleared and called for help.
Firefighters responded to that blaze, called the Balcom Fire, and held it to 1.8 acres using water lines, hand tools, a bulldozer, helicopters and a C-130 air tanker.
After forward progress was stopped, a bulldozer cleared a containment line around the burn area and the air tanker dropped fire retardant to keep the fire from spreading. Firefighters used hoses to extinguish burning material and soak the ground.
The following morning, a fire department drone with an infrared camera identified heat signatures: one near the dozer line and several by the wheels of the tractor near the center of the burn area. Personnel dug out the hot spot near the dozer line and eliminated it. The heat signatures on the tractor did not appear unusual since the heavy, metal rims would have retained heat overnight.
After assessing the conditions and the containment measures in place, the decision was made to close the incident and return control of the property to the owner.
Over several days, the burn area was visited multiple times by civilians. None of them saw or reported any indication of smoke or fire. Additionally, there was measurable rain in the area Nov. 2.
On Nov. 5, 2024, the National Weather Service declared a Particularly Dangerous Situation for the following morning, marked by extreme weather, including dry conditions, low humidity and powerful, gusty winds.
The arson investigation determined that those extreme winds dislodged a previously covered pocket of hot debris from the remains of one of the tractor’s tires, gave it the oxygen needed to burn and carried that fire beyond the containment area where it ignited dry vegetation, starting the Mountain Fire.
“We used all the technology at our disposal to contain and suppress the initial fire,” Gardner said. “With the extreme weather conditions of Nov. 6, that wasn’t enough.”
“This fire serves as a warning for all of us about the risk wildfire poses to our community and the importance of risk-reduction practices,” he said.
Gardner announced three steps the fire department will take to enhance operations moving forward.
An independent, third-party review of operations on the Balcom Fire,
Review, enhance and update the department’s policy for mop-up procedures on wildfires,
And creating a new policy for monitoring previous burn areas.
“The Ventura County Fire Department exists to serve our community in support of public safety,” Gardner said. “We constantly evaluate and update our standards, operations and equipment to deliver the most effective emergency response we can. Lessons learned from this fire are already shaping how we will prepare for and respond to future wildfires. Our commitment to our community will not waver.”