The raging, out-of-control wildfires across Northern California have now killed at least 31 people, marking the deadliest week of wildfires in state history, officials said late Thursday.
Sonoma County Sheriff Robert Giordano said Thursday night that two more people have been confirmed dead there. That raises the statewide death total from 29 to 31. While no one fire currently burning has killed that many, collectively this is the deadliest series of simultaneous fires in the state since records have been kept.
The fires, most of them in wine country, broke out almost all at once on Sunday night and have exploded to cover more than 300 square miles, an area as large as New York City.
The flames may have been sparked by downed power lines and blown transformers, according to emergency radio traffic.
State officials have not yet officially said what caused the blazes that have destroyed at least 3,500 homes and businesses. But dispatch audio obtained by KTVU Fox 2 News reveal firefighters in Napa and Sonoma Counties called in more than a dozen reports of downed power lines, live wires, and blown transformers late Sunday in the first hours of the wildfire outbreak.
Multiple fires were reported by firefighters near the sites of downed power lines and fallen trees.
In one radio exchange between firefighters in Napa County, crews called in downed lines and a blown transformer around 9:15 p.m. Sunday. About 15 minutes later, crews also reported a fire in the same area. It was unclear if that particular fire grew into a larger blaze or was contained, according to KTVU FOX 2.
The owner of the power equipment, Pacific Gas and Electric Company, said in a statement Wednesday "hurricane-strength winds in excess of 75 mph," and "millions of trees weakened by years of drought and recent renewed vegetation growth from winter storms, all contributed to some trees, branches and debris impacting our electric lines across the North Bay."
"In some cases we have found instances of wires down, broken poles and impacted infrastructure. Where those have occurred, we have reported them to our state utility regulator and CalFire," the company said. "Our thoughts are with all those individuals who were impacted by these devastating wildfires. We want our customers, families and friends to know that we will stand beside them and work together throughout this restoration process."
The company, just like all utility companies in California, is required to keep vegetation more than 10 feet away from its power poles and towers, and to remove flammable debris from around the surrounding ground, according to KTVU Fox 2.
Utility companies in California have previously been found responsible for major wildfires due to inadequate maintenance of their power infrastructure.
The state Public Utilities Commission fined PG&E for $8.3 million in April for failing to maintain a power line that sparked a fire in September 2015 that killed two people and destroyed 549 homes, according to the East Bay Times.
CalFire announced last year that it will seek to force PG&E to pay $90 million in firefighting costs for that blaze, the newspaper reported. A spokesperson for the company told the East Bay Times questions about maintenance of the lines in relation to the current wildfires were “highly speculative.”
While authorities work to figure out an official cause of the fires, the blazes could expand Thursday because the area is expecting wind gusts up to 45 mph, with nearly non-existent humidity in areas north of San Francisco.
"It's going to continue to get worse before it gets better," state fire Chief Ken Pimlott said Wednesday.
The 22 fires spanned more than 265 square miles, many of them completely out of control. Modern, strategic attacks that have kept destruction and death tolls low in recent years just haven't worked against its ferocity.
"We are literally looking at explosive vegetation," Pimlott said. "Make no mistake…this is a serious, critical, catastrophic event."
Gov. Jerry Brown said the fires were "one of the biggest, most serious, and it's not over."
Helicopters and air tankers were assisting thousands of firefighters trying to beat back the flames. Until now, the efforts have focused on "life safety" rather than extinguishing the blazes, partly because the flames were shifting with winds and targeting new communities without warning.
Giordano said hundreds of people were still reported missing, but officials believe many of those people will be found. Chaotic evacuations and poor communications over the past few days have made locating friends and family difficult.
But the sheriff said he does expect the death toll to climb.
"The devastation is enormous," he said. "We can't even get into most areas."
The Associated Press contributed to this report.