The so-called Park Fire had burned almost 350,000 acres (142,000 hectares) as of late Saturday morning, making it the seventh-largest ever recorded in California history, the state agency Cal Fire said on X.
The fire, which prompted orders for more than 4,000 people to flee their homes, was burning through a largely rural, mountainous area near the city of Chico, some 90 miles (145 kilometers) north of state capital Sacramento.
"Extreme fire conditions continue to challenge firefighters," it said.
For now it is "zero percent" controlled, despite the efforts of about 2,500 personnel with over a dozen helicopters and several planes, according to the agency.
"The Park Fire continued to burn aggressively due to steep terrain and winds. Extreme fire behavior has occurred due to the slope and winds aligning, causing significant growth," Cal Fire said in an update Saturday.
It however noted that cooler weather and higher moisture was expected in the region.
The fire started Wednesday near Chico, in Butte County, and within hours had devastated a wide area there and in neighboring Tehama County.
The latest update showed 134 structures had been destroyed by the fire.
The blaze has generated an enormous column of dense gray smoke which has also been blown over nearby states.
On Thursday, police detained a 42-year-old man on suspicion of having started the fire by pushing a burning car into a ravine.
Some area residents, such as Julia Yarbough, have already seen their homes reduced to ashes.
"This is what's left of my house," she told CBS on Friday, showing the blackened and still smoking debris.
Chico is only about 15 miles from Paradise, a city devastated by a 2018 fire that ranked as California's most deadly ever, claiming 85 lives.
The explosive growth of the Park Fire has again placed Paradise under evacuation warning, unleashing painful memories for its residents.
Experts say climate change, accelerated by human action, is leading to more extreme weather events.
