© Justin Sullivan/Getty ImagesThe Kincade fire consumed homes in Geyserville, California.
Pacific Gas & Electric (PG&E) initiated the precautionary blackout - expected to be the largest in state history - due to forecasts of extreme winds, which it said could damage facilities and cause new fires.
California Governor Gavin Newsom said the outages were "unacceptable".
Some 90,000 people have been ordered to evacuate towns in northern California.
The new evacuation order encompasses a huge area of Sonoma County, where the Kincade Fire has already burned through 25,455 acres (10,300 hectares) of land.
A state of emergency has been declared in Los Angeles and Sonoma counties, and thousands of firefighters are battling the blazes.
Why is the power being switched off?
PG&E said the power cuts would affect 940,000 households and businesses across 36 counties in northern California - hitting an estimated two million people. The outages are expected to last until Monday.
"We have begun implementing the public safety power shutoff", a PG&E official confirmed in a press conference on Saturday evening.
In a statement the previous day, PG&E warned customers that they could be affected by a mass blackout, citing forecasts of potential extreme weather.
The warning came as the company faced scrutiny over its possible role in the fires.
The Kincade Fire in northern California began seven minutes after a nearby power line was damaged, but PG&E has not yet confirmed if the power glitch started the blaze.
The company is already seeking bankruptcy protection as it faces lawsuits over last year's Camp Fire, which killed 85 people. The deadliest wildfire in the state's history was sparked by ageing equipment owned by PG&E. It spawned billions of dollars in liability claims against the company.
In a video posted to Twitter on Saturday, Governor Newsom said the power cuts were "infuriating everyone, and rightfully so".
"We are going to do our best to get through these high wind events...and get these lights back on and do everything in our power to make sure PG&E's never in a position where they're doing this to us again," he said.
What's the forecast?
The Kincade Fire was about 10% contained as of Saturday evening local time.
The fire was burning in remote, steep terrain, making access difficult, the state fire department said.
Winds in the region were expected to pick up on Saturday night and gusts were forecast to hit 85mph (137km/h).
The National Weather Service issued a "red flag" warning for areas around the Kincade Fire.
In suburban Los Angeles, the Tick Fire had charred 4,615 acres and was 55% contained as of Saturday evening. All residents who were told to evacuate have returned home.
Firefighters have also been battling several other blazes in the state.
'Seconds to get out'
BBC correspondent Peter Bowes lives in the Santa Clarita area north of Los Angeles, where the Tick Fire has been raging.
"My partner was in the house and had just seconds to get out, to pick up the dog, throw the dog in the car - gently - just get out. It happened that quickly and all our neighbours did exactly the same thing," he said on Friday.
He later tweeted photos of the devastation.
Why can't anyone at the editorial level at SOTT believe that governments could actually influence the weather? And that this program might be further along than anyone could ever believe? This is aside from real, long-term solar and galactic cycles that influence the weather; that has been documented. The sun drives our weather and NOT CO2.
But: why can't anyone at SOTT ever think that the elite psychopaths KNOW about these cycles, and they may have devised ways to use natural cycles to their advantage? That they may have actually learned to control the weather in advance of the solar minimum so that they could reap the greatest harvests from it? Check this out:
[Link]
That is a link to a United States Senate document, authored by Vanevar Bush, that details the entire world-wide geoengineering program from its inception up to 1979. That document in itself shows that our governments have been working to alter the weather for decades before the present. Some of what is referenced in that document I can attest as the TRUTH, as I was a teenager in California during the drought of 1977-78 when cloud seeding was attempted. Also, the work done to create rainfall in Vietnam jungles was well known.
This shit not only *has* happened in the past, but it IS happening NOW, on a much larger scale. Can anyone even conceive of how much more they can do NOW, forty years later??
WAKE UP SOTT. This shit is going on NOW, and is using the same technology that brought down the towers on 9/11. It's time to pull your heads out and acknowledge that hidden technology is now being used against the masses by the psychopaths in power, and the sooner we all recognize this fact the more time we have to band together to STOP IT.