Investigators Look Into Downed Power Lines, Exploding Transformers as Possible Cause of Fires

State fire investigators are looking into a possible connection between failures in Pacific Gas & Electric Co.'s electrical infrastructure and the devastating wildfires sweeping through Northern California.

The Bay Area News Group reported Wednesday that Sonoma County dispatchers sent fire crews out to at least 10 locations over a 90-minute period, starting around 9:20 p.m. on Sunday, to respond to calls about electrical problems.

Cal Fire spokeswoman Janet Upton said the agency is investigating whether reports of power lines falling down and electrical transformers exploding in Sonoma County Sunday night may have caused some of the wildfires in the region.

The agency stresses that it’s investigating a number of potential causes. PG&E spokesman Jason King said the crews found wires down, broken poles and impacted infrastructure.

But he blamed the historic nature of the hurricane-strength wind -- and trees weakened by years of drought impacting the company’s electric lines.

Cal Fire investigators determined the 2015 Butte Fire was started by a PG&E line coming in contact with a tree. State regulators fined the utility more than $8 million for failure to properly maintain the lines.

Authorities say the wildfires currently raging -- some of the most destructive in California’s history -- have killed 21 people so far. Eleven people have died in Sonoma County, six in Mendocino County, two in Napa County and two in Yuba County.

The blazes have burned almost 170,000 acres across Northern California with little containment, according to Cal Fire. Sonoma County officials said Wednesday that hundreds of people have been reported missing during the fires and that more than 100 have been located safely. People can call 707-565-3856 to report missing persons.

KQED's Ryan Levi and Peter Jon Shuler contributed to this post.