Spark from hammer, metal stake caused Ranch fire in 2018, California’s largest wildfire
California’s largest wildfire was ignited by a scattered spark or hot metal fragment formed when a Potter Valley rancher used a metal hammer last summer to drive a large metal stake into a yellow jacket nest on a dry, grassy slope on his Highway 20 ranch, Cal Fire said Thursday.
The result was the Ranch fire — a conflagration that consumed more than 641 square miles of landscape as it stormed into Lake County and the vast Mendocino National Forest, eventually reaching into Colusa and Glenn counties.
A Utah firefighter, Draper Fire Department Battalion Chief Matthew Burchett, lost his life fighting the blaze, which started July 27 and raged through remote countryside for a month. The rampaging fire destroyed or damaged 280 structures mostly north of Clear Lake, including 138 single-family homes and one multifamily residence, Cal Fire said.
Together with the 49,000-acre River fire, which began about an hour later near Hopland, the 410,203-acre inferno became known as the Mendocino Complex fire, one of several dozen incidents that would make 2018 the deadliest and most devastating wildfire season the state of California and the nation have ever seen.
The cause of the River fire has not yet been announced.
State fire officials said the investigative findings in the Ranch disaster serve as reminder that even a small, everyday act can lead to disaster if conditions are ripe for fire.
It’s a pertinent message, amid warming temperatures and drying fuel loads grown abundant in the wake of spring rains, officials said.
“You’ve heard me talk about it so many times last year alone, what we’re dealing with,” Cal Fire spokesman Scott McLean said, warning in his tone. “One spark.”
According to the 20-page investigative report released Thursday, the Ranch fire started when a rancher whose name was redacted from the document went to erect a shade cloth above some groundwater tanks on his ranch at 5400 East Highway 20, not far from the Mendocino-Lake county line. He told investigators the last suspended shade had blown down some time earlier, and his daughter had told him their livestock were being supplied with water that was too hot from at least one of the 2,500-gallon tanks clustered together on the hillside, according to the report. The man told a Cal Fire investigator, Fire Capt. Specialist Eric Bettger, that he had used a four-wheel vehicle to pull a trailer with supplies up the hill to put up the sun shade but had agitated an underground yellow jacket’s nest before he could make any real progress, Bettger wrote.
Being allergic to bees, he waited about an hour to allow the insects to stop swarming. Then he took a claw hammer and quickly pounded a 24-inch concrete stake 10-to-12 inches into the ground to plug the yellow jacket hole before he smelled smoke and realized the tall, 2-to-3-foot grasses had begun to burn just behind him, the report said.
It was about 100 degrees outside, and the 2-by-2-foot patch of flames spread quickly to the large shade cloth lying on the ground nearby and continued to grow, despite his frantic efforts to try to douse the flames.
The rancher told Cal Fire personnel he tried to shovel dirt onto the fire but found the ground too hard to dig up. Then he tried to smother the flames with a nearby trampoline, a rug and the part of the shade cloth, which just burned.