Juliet Williams and Don Thompson, Associated Press
Downed power lines caused a dozen Northern California wildfires last fall, including two that killed a total of 15 people, California's Department of Forestry and Fire Protection said Friday. The wildfires were part of a series that were the deadliest in California history.
The agency said in a report that investigators determined the fires "were caused by electric power and distribution lines, conductors and the failure of power poles."
All involved equipment owned by San Francisco-based Pacific Gas & Electric Co. A message left with PG&E was not immediately returned Friday afternoon.
The fires were part of a series of blazes that raged through wind-whipped California last October that killed 44 people, destroyed 8,800 structures and forced more than 100,000 people to evacuate. About 11,000 firefighters from 17 states and Australia helped battle the blazes.
The deadly fires in Friday's report burned in Mendocino and Napa counties.
In the Mendocino blaze, investigators said Potter Valley experienced wind speeds up to 67 mph, causing many tree branches to fall, triggering numerous 911 calls reporting fires.
"An arc from a conductor was witnessed along with the start of a vegetation fire," the report said. A second fire also was "from an overhead conductor." The two sparked a third, merged, and burned 10 miles (16 kilometers), the report said. A responding firefighter said the smoke was blowing sideways and he had to veer around numerous tree branches in the road to get to the fire area.
One homeowner told the firefighter "he saw a tree illuminate when the conductors arced."
Another property owner told Fire Captain Specialist Eric Bettger "he saw a flash to the east and saw the conductors come down. ... He said the fire crossed the road within seconds."
Hundreds of homeowners and relatives of those killed have sued Pacific Gas & Electric Co. in the wake of the deadly blazes.
Sen. Bill Dodd, a Democrat who represents the Napa area, called the report's findings "disappointing and deeply concerning."
"I'm calling on PG&E, utilities across the state and the Public Utilities Commission to step up and ensure they are meeting their legal obligations to maintain power lines in a safe manner," Dodd said in a statement. "It's inexcusable and it can't be allowed to happen again."
Dodd has introduced legislation that would require electric utilities to update wildfire plans to determine when they need to cut power to lines during harsh weather and boost infrastructure.
PG&E announced in October that it would start switching off power to minimize sparks in vulnerable areas during times of extreme fire danger after local officials and fire survivors had urged the cutoffs after deadly blazes. PG&E and some other state utilities previously have resisted it, arguing that cutting off power carries its own risks, including to patients dependent on electrical equipment.
CalFire investigators are still probing other fires in October and December, including the deadliest blaze in Napa and Sonoma Counties, which PG&E has argued was started by wires belonging to a private homeowner.
Thompson contributed to this report from Sacramento, Calif.