Shares of two utility companies have plunged as deadly California wildfires scorched thousands of acres and continue to threaten lives and property, and as state regulators opened investigations.

Pacific Gas & Electric shares tumbled as much as 27 percent. They climbed partly back, closing down 17 percent. Edison International shares closed down 12 percent.

Both utilities are grappling with power outages affecting tens of thousands of customers, and said they have submitted initial incident reports to state regulators.

Hundreds of thousands of people have been evacuated or forced to flee the affected regions.

The Mercury News reported that state regulators were looking at the utilities' facilities in the affected areas "to asses the compliance" with applicable rules and regulations. PG&E and Edison have reported that their electrical infrastructure malfunctioned near the heart of the two fire-ravaged areas in the state, the paper said.

There are the Woolsey and Hill fires, which have burned through areas near Los Angeles, including Malibu, Westlake Village and Thousand Oaks. And the Camp Fire in Northern California has killed at least 71 people, now the most destructive and deadliest in state history, according to the Los Angeles Times.

The parent company of public utility Southern California Edison said wildfires left more than 23,000 customers without power in Ventura and Los Angeles counties. Over the weekend, Southern California Edison said it has submitted "an initial safety incident report on the Woolsey Fire."

"The information in the report is preliminary. There has been no determination of origin or cause of either wildfire. SCE will fully cooperate with any investigations," the company said.

Earlier, PG&E said the Camp Fire has also cut power to 25,000 customers. It said it also provided a preliminary report to the state regulator and that it will "fully cooperate with any investigations."

The Mercury News said PG&E had reported an outage on a transmission line near the area where Cal Fire officials believe the Camp fire originated shortly before it was first detected. And Edison reported an issue on a substation circuit shortly before Cal Fire estimates the Woolsey fire began.

The Southern California blaze has killed three people and forced evacuations in Malibu, Calabasas, Agoura Hills and Thousand Oaks, a day after a gunman killed 12 people at a bar there.

Among those whose homes were destroyed are Miley Cyrus, Gerard Butler, Robin Thicke and Shannen Doherty, according to The Associated Press.

Story Date: December 4, 2018