Cal Fire has determined last year’s Ranch Fire, California’s largest in history, was ignited by a spark or hot metal fragment created by a Potter Valley rancher hammering a metal stake into the ground.
According to Cal Fire’s 20-page investigative report issued Thursday (June 6, 2019), the July 27 fire was caused by a rancher attempting to erect a shade cloth above some ground water tanks on his ranch because a previous shade had blown down and the water was too hot for his cattle.
The rancher – whose name was redacted from the report – told Cal Fire investigator Eric Bettger that he was preparing to put up the sun shade when he agitated an underground yellow jacket’s nest.
The rancher said he was allergic to bees, and he waited about an hour to allow the insects to stop swarming. He then used a claw hammer to quickly pound a 24-inch stake 10-to-12 inches into the ground. It was then he smelled smoke and realized the tall grasses nearby had begun to burn, the report said.
Despite the rancher’s frantic efforts to extinguish the fire, it continued to grow and quickly spread out of control. Cal Fire’s deputy director, Michael Mohler, told the Fresno Bee that incident was a “complete accident,” and that no charges will be filed.
The resulting fire consumed more than 641 square miles, crossing the Mendocino line into Lake County and the Mendocino National Forest, eventually spreading into Colusa and Glenn counties. A firefighter, Draper Fire Department Battalion Chief Matthew Burchett, was killed fighting the blaze. The fire destroyed or damaged 280 structures.
Together with the 49,000-acre River Fire, which began an hour later near Hopland, the 410,203-acre inferno became known as the Mendocino Complex Fire.