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High Winds, Arcing Power Lines Blamed For Devastating Cascade Fire

Megan Goldsby
October 10, 2018 - 10:43 am

One year after wide swaths of Northern California were destroyed by fire, the final verdict is in on one of the scores of wildfires that erupted over a 48-hour period starting on October 8, 2017. 

CalFire investigators have concluded that the Cascade Fire in Yuba County, which killed four people and destroyed hundreds of buildings, was started by gusty winds knocking down power lines.

The strong gusts led power lines to touch, a term called line slap, said CalFire Deputy Director Mike Muller. That contact released an electrical arc that started the fire and was almost hot enough to melt metal, he said. 

"That was not preventable, that was simply mother nature at her worst," said Muller. "Unfortunately, what resulted out of it was the Cascade Fire."

People in the North Bay are all too familiar with the power of the record-breaking winds that blew up over those two days and spread flames far and wide. The destruction from the Cascade Fire hit near the community of  Loma Rica, about 15 miles northeast Marysville, in the heart of California's Gold Country. 

PG&E released a statement about the Cascade Fire probe saying it is reviewing the agency's findings. The electrical utility said it has already taken precautionary measures to remove flammable materials like brush and vegetation from fire-prone areas,  improve weather forecasting, and strengthen lines and poles. 

"There are some things that just can't be prevented, but there are other areas we can look at. After the North Bay and really all of last year, we're definitely seeing improvements," Muller said about PG&E's efforts. 

CalFire has wrapped up most of its investigations into the North Bay fires. But there's still no definitive answer as to what caused the Tubbs Fire, the fire that swept through Santa Rosa, burned thousands of homes, and left at least 22 people dead.  

"We are still under investigation with the Tubbs," Mueller said. "That could take several more months."

And beyond the North Bay, additional investigations continue. "We have to remember we had over 170 fires just in that window in October. That's taking several thousands hours of investigative work, plus a lot of personnel to support those. So, yes, we still have some outstanding," Muller said. 

Written by Diana Shook.