What started California's wildfires? Theories range from arson to downed PG&E power lines

Authorities say just about anything could have started any one of the wildfires now tearing through Northern California.

Fire officials have not yet determined the cause of any of the 17 major fires burning north of San Francisco.

They say anything from a carelessly discarded cigarette, a downed power line, a car's backfire or a chainsaw's pull could all be a possible ignition source.

One woman speculated to KTVU on Monday that it could be an arson bug who waited for high winds to set the blaze.

The Bay Area News Group reported that emergency dispatchers in Sonoma County received multiple calls of power lines falling down and electrical transformers exploding on Sunday night, when the wildfires were first reported.

In all, according to a review of emergency radio traffic by the Bay Area News Group, Sonoma County dispatchers sent out fire crews to at least 10 different locations across the county over a 90-minute period starting at 9:22 pm to respond to 911 calls and other reports of sparking wires and problems with the county’s electrical system amid high winds.

PG&E officials issued a statement Tuesday evening, acknowledging the equipment troubles even as a company spokesman called the questions about maintenance “highly speculative.”

The Associated Press contributed to this report.