As high-voltage lines got loose and whipped around, striking the metal tower, molten aluminum and metal sprayed across tinder dry vegetation, igniting the brush. Arriving firefighters could only watch as the blaze underneath the power lines quickly spread to wild timber and brush.
That's the horror story about the ignition of the
Now a month after the blaze first roared to life along the North Fork of the
"It's there that the likely (O-ring) connection failed," said
Within hours, the town of Paradise was nearly wiped off the map. At least 85 people died in the fire, and it's destroyed more structures than any other wildfire in this flammable state's history.
As investigators narrow their focus on the cause,
Numerous lawsuits have been filed against the utility, and its stock price has imploded. CPUC investigators also have begun investigating if
'Shower of molten metal'
On Thursday, a reporter and photographer left Pulga and drove up the winding, dirt
Loose wires dangled from the tower, severed after investigators removed various parts as evidence. Private
Catastrophic fire expert
"There's so much energy there even green vegetation could ignite because it fries the moisture out of anything it hits," he said. "It chars that, and then the charcoal becomes the conductor."
DeHaan said he's seen examples where a transmission line hit the ground and transformed the sand into a glassy column, similar to a fulgurite , a form of fused soil created by a lightning strike.
"All of those towers fatigue, and they can get a fatigue crack and with high winds it can start flexing back and forth until it fails," DeHaan said, describing what would happen when the energized line slapped into the structure or the ground. "That would melt the conductors and generate a shower of molten metal as well as the extremely hot plasma in the arc itself."
If an O-ring hook or other structure is weakened by metal fatigue and breaks, the insulators are no longer supported and can come in contact with the lines and the tower.
De Ghetaldi said "jumper" cables, which are used to switch currents between transmission lines on the tower, as well as the transmission and distribution lines themselves, should be insulated with rubber coating, similar to a lamp cord. He said the utilities balk at the safety measure because it's more expensive and adds weight to the lines.
"If the jumper wire had been insulated, the whole thing would've been prevented," he said.
"Certain conditions can lead to metal corrosion. (Investigators) will look at age and previous exposure to wind," she said. "Making sure utilities are paying attention to aging infrastructure is absolutely imperative. They should've been assessing if there were risks to ... the aging towers, particularly since nearby towers suffered wind damage."
In 2012, a winter storm toppled five towers on the same transmission line. Those crumpled towers were replaced in 2016, but other towers were not, attorneys have alleged.
Sandoval called a failure on a metal transmission line "extremely unusual," especially compared to more fragile distribution lines on wooden poles.
"Was the cross arm showing signs of stress? Should equipment have been more quickly replaced?" Sandoval asked.
Fire investigators also have retrieved a power pole and other evidence from the location of the second power line malfunction in Concow on the Big Bend 12,000-volt distribution line, about two miles west of Pulga. Trees and two wood power poles litter the ground near a single orange construction cone that marks the spot.
In Sandoval's article, she included photos she took of dangerous power lines. Something must change, she concluded.
"Stemming utility-caused wildfires is a legal and ethical imperative to protect the safety and health of the people of
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