A charred vehicle is seen in the parking lot of the burned Oak Park Motel after the passage of the Santiam Fire in Gates, Oregon

California firefighters battled the state's largest ever inferno Thursday, as more than half a million people fled blazes up and down the US West Coast and officials warned the death toll could shoot up in coming days.

At least eight people have been confirmed dead in the past 24 hours across California, Oregon and Washington, but officials say some areas are still impossible to reach.

The August Complex Fire became the biggest recorded blaze in Californian history on Thursday, after multiple fires in the state's northwest combined in high temperatures and winds to rip through 470,000 acres of dry vegetation.

Half a million people have been evacuated in neighboring Oregon, authorities said.

"Firefighters are prioritizing life (and) safety as they battle a record 900,000 acres of wildfires," said an Oregon government statement.

Governor Kate Brown said that the amount of land incinerated by fires in just the last 72 hours was twice the state's annual average, and that at least five towns had been "substantially destroyed."

"We have never seen this amount of uncontained across our state," she told a press conference.

"We know that there are fire related fatalities. And as soon as we are able to provide confirmed information, we will do so."

A sign is posted next to a fire vehicle as flames continue to consume the area during the Creek fire in Fresno County, California

Local Oregon officials have confirmed two deaths in the Santiam Canyon region, 60 miles (95 kilometers) south of Portland, and another was recorded in the Ashland area, near the California border.

Police went door to door to make sure that residents were evacuating the Molalla, marking their driveways with spray paint to show they had left.

"It's one thing to leave your house, it's another thing being told that you have to leave," said Denise Pentz, a resident of the town for 11 years, who was loading her family belongings into a camping trailer.

"It's awful. This is home... But the most important thing is my babies, my husband, my dog, my cat, and that all my neighbors have gotten out safely."

All three West Coast states have been scrambling to contain rapidly spreading wildfires since the weekend due to unprecedented heatwaves followed by intense, dry winds.

Among those killed in the past day was a one-year-old boy who perished while his parents suffered as they attempted to flee an inferno 130 miles east of Seattle.

An orange smoke-filled sky is seen above cows in Molalla, Oregon, as fires burn nearby

"This child's family and community will never be the same," said Washington governor Jay Inslee, in a statement on his state's first fire death of 2020.

"And neither will countless others who are reeling from the utter devastation these wildfires are leaving in their wake."

'Glowing red'

In northern California's Butte County, where three people have been killed, firefighters battled flames through the night after a day of apocalyptic orange skies over the Golden State.

Another dozen people were reportedly unaccounted for in the area.

One unidentified person was killed in far northern California, near the remote rural community of Happy Camp, a Cal Fire spokeswoman told AFP.

Tina Rose, 29, fled her home in central California after witnessing a nearby mountain "glowing red" from looming wildfires.

A charred swing set and car are seen after the passage of the Santiam Fire in Gates, Oregon

"It is something we never want to experience again," she told AFP, speaking from her brother-in-law's crowded home near Fresno.

In the San Francisco area, Wednesday's deep orange sky caused by wildfire smoke gave way to a wintry gray, but cars were still forced to drive with lights on in the gloom.

Polluted air meant schools and daycare centers were no longer letting children play outside, while seniors were encouraged to stay inside.

But the strong, dry winds of the past days eased off across much of the state, with severe weather warnings lifted for most of California. Humidity is expected to rise as temperatures cool through to next week, providing some relief, Cal Fire said.

Death toll rises

Much of the smoke has blown down from the north, where the Bear Fire exploded at an unprecedented speed this week, combining with older blazes to threaten the town of Oroville.

  • Firefighters cut defensive lines and light backfires to protect structures behind a CalFire fire station during the Bear fire

  • Map of the western coast of the US, showing active wildfires as of September 10, and highlighting the main fires in California.

By Thursday it had covered 250,000 acres and was only 23 percent contained.

Evacuation warnings were expanded to parts of the town of Paradise, the site of California's deadliest modern fire, which killed 86 people less than two years ago.

Including eight California fire deaths last month, the region's total reported fire is now 16 for the year.

California has seen more than 3.1 million acres burn this year—an annual record, with nearly four months of fire season still to come.

Governor Gavin Newsom blamed the ferocity of this year's fires on climate change.

"We must do more," he tweeted. "We need action at EVERY level. CA cannot do this alone. Climate change is REAL."