Il Nuovo Postiglione - Thousands evacuate season's biggest wildfire in northern California

Fueled by a crushing heatwave, the so-called Park Fire -- the most intense wildfire to hit the state this summer -- has rapidly devoured 164,000 acres (66,000 hectares) and is continuing to gain strength.

For now it is "zero percent" controlled, despite the efforts of some 1,600 firefighters, according to state agency Cal Fire.

A total of 4,000 people have evacuated the towns of Cohasset and Forest Ranch, and an additional 400 from the small city of Chico.

The blaze so far has destroyed 134 structures, authorities said.

The fire started Wednesday near Chico, in Butte County, and within hours had devastated a wide area there and in neighboring Tehama County.

The blaze has generated an enormous column of dense gray smoke, gritty clouds akin to those of a huge and violent storm that are now visible in nearby US states.

"The Park Fire continues to burn very actively," Butte County sheriff Kory Honea said Thursday.

Fire departments from across the state have sent crews to lend a hand.

The National Weather Service has issued a Red Flag Warning for the region through Friday night, predicting "critical" fire weather conditions.

On Thursday, police detained a 42-year-old man on suspicion of having started the fire by pushing a burning car into a ravine.

Butte County prosecutor Mike Ramsey identified the man as Ronnie Dean Stout and said he would be held without bail until a court appearance next week.

- 'Prepared to go' -

"You have to be prepared to go," Sheriff Honea warned area residents.

"This county has seen time and time again where people have waited too long and they have lost their lives," he added.

Some area residents, like Julia Yarbough, have already seen their homes reduced to ashes.

"This is what's left of my house," she told CBS, showing the blackened and still smoking debris of her house.

"I must be in shock."

Butte County is about 70 miles north of state capital Sacramento and just 25 miles from Paradise, the city that was 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.

"I would call its behavior extraordinary," said UCLA climate scientist Daniel Swain, adding, "that's not a good thing."

The only silver lining, he said, is that it is not headed toward any large cities.

California is experiencing an early start to what appears to be an intense wildfire season, with 20 currently active incidents.

An additional 40 blazes are threatening communities to the north, in the states of Washington and Oregon.

Canada has also seen a spate of wildfires, including a huge blaze that has consumed much of the tourist town of Jasper in western Alberta province.

Experts say climate change, accelerated by human actions, is leading to more extreme weather events.

S.Maiolo--INP