(CNN) -- Whipping winds and dangerously dry conditions are fueling California's wildfires Sunday, with more trouble expected later this week.
The Kincade Fire, which has already destroyed 79 structures north of San Francisco Bay, is now threatening 31,175 other homes or other buildings, said the California Department of Forestry and Fire Protection (Cal Fire).
About 180,000 people in Sonoma County are under evacuation orders, the sheriff's office said.
"This is the largest evacuation that any of us at the Sheriff's Office can remember," the department tweeted. "Take care of each other."
Down in the Los Angeles area, "critical fire weather conditions are in place across Southern California today as winds ramp up across the region this evening," CNN meteorologist Haley Brink said.
The Tick Fire, which is burning near Santa Clarita, had destroyed at least 22 structures and was threatening 10,000 more, the Los Angeles County Fire Department said Sunday.
Ferocious winds (with gusts up to 80 mph) mixed with dry vegetation and critically low humidity (of less than 10%) have spawned the extreme fire threat, Brink said.
Several areas are under red flag warnings, which are issued when a weather event could lead to "extreme fire behavior that will occur within 24 hours," Cal Fire said.
That brings the possibility for "very rapid fire spread and extreme fire behavior with any new ignitions Sunday night into Monday," the National Weather Service in Los Angeles said.
"A second, potentially stronger Santa Ana wind event is forecast to occur Wednesday into Thursday, with winds gusting to 70 mph," Brink said.
The Sonoma County Sheriff's Office issued a dire warning:
"You need to leave now while you still can."
More than 1 million people in the dark
In an effort to avert any more wildfires, Pacific Gas & Electric has shut off power to 960,000 customers, PG&E said Sunday.
But the number of actual people without power is higher, since electric customers include houses and businesses.
Residents in parts of 38 counties in the Northern and Southern Sierra Foothills, the North Bay and Mendocino, the Bay Area, the Central Coast and the Central Valley are part of the rolling blackouts, the company said.
PG&E announced the current shutoff last week. The company has made preventative shutoffs all over northern and central California in recent weeks, but this one could be the largest.
"This (public safety power shutoff) action is based on forecasts of historic dry, hot and windy weather that poses a significant risk for damage and sparks on the electric system and rapid wildfire spread," PG&E said.
San Jose City Manager Kip Harkness said the city has a plan in place for the outage, which could affect about 90,000 in the area. Officials said the city has activated a "power vulnerability plan" that has been months in the works.
Californians tired of losing electricity might have to get used to it.
Earlier this year, the company warned it could proactively cut power more often during risky weather conditions as a means of preventing wildfires caused by high winds downing live power equipment.
The preventive power outages may continue for a decade, PG&E's chief executive said earlier this month.
PG&E has came under widespread criticism and agreed to pay billions for its role in the 2018 Camp Fire, California's deadliest and most destructive blaze.
A Cal Fire investigation found the company responsible for the fire. PG&E acknowledged it's "probable" that its equipment started the fire.