Experts say PG&E ignored apparent danger signs leading up to the Dixie Fire and kept power flowing hours after a tree fell onto the line, where it eventually sparked the fire that has now grown to a quarter million acres.
The July 13 fire was touched off in the afternoon along PG&E’s Bucks Creek 1101 circuit, which runs along the steep Feather River Canyon in Plumas County.
PG&E’s account of events leading up to the fire, submitted to a federal judge overseeing its probation in the San Bruno gas explosion, notes that just before 7 a.m. the day of the fire, there was a short-circuit on the Bucks Creek line.
It was when, the utility says, a 70-foot tall Douglas fir fell onto the line near the Cresta Dam.
The power fluctuated for a fraction of a second. It triggered two fuses to blow, cutting power to the nearby dam. But it was too short to trigger automated equipment that could completely shut down the line. The company did not say in its filing why it did not remotely shut down the entire system.
“PG&E had enough information, they should have put it together to know they should have shut off the power to their line,” said Ken Buske, an electrical engineer who has investigated the cause of fires for 40 years. “They should have assumed that either a fire started right then, or at least they needed to remove the power from the line.”
It took several hours for the lineman to arrive where those fuses failed. By that time, it was late afternoon and the fire was already going.
“What likely happened, is that all day long that tree limb was rubbing on the line -- on an uninsulated power line -- like a bow against a violin,’’ said former CPUC commissioner Catherine Sandoval, who is advising Judge William Alsup as he oversees the company’s criminal probation.
“This devasting fire could have been prevented by recognizing the danger of these voltage fluctuations, especially in these rural, high fire threat areas,” she said.
NBC Bay Area’s Investigative Unit has learned that PG&E recently ranked the Bucks Creek line as No. 11 on its list of highest risk circuits for equipment sparked wildfire, and ranked it at moderately high risk for fires sparked by tree contact with lines.
PG&E hoped to underground that part of the line where the started. In April, it summoned officials from Cal Fire, the state Public Utilities Commission and an energy consulting firm advising Gov. Gavin Newsom to the line, hoping to expedite a plan to underground it.
In a statement, the utility said it sought to convey that it believed the Bucks Creek undergrounding project was at “high risk of delay for completion due to multiple government permitting requirements.”
At the time of the fire, however, PG&E had yet to file for those permits and the project was in the engineering and estimation phase, the company said.
Buske said the lax response to the incident belies the company’s stated concerns about fire danger.
“It’s kind of like the guy who says this line is at high risk is in one room,” he said, “and there’s another room where the guy doing the response is sitting. And he never knows about the guy in the room next door to him. It’s like they don’t communicate and they don’t think there needs to be a response when there’s a high risk.”
PG&E on Friday offered no further comment beyond what was contained in its reports to regulators and the judge about the fire.