Officials in West Coast states where record fires have killed 35 people accused President Donald Trump on Sunday of being in denial about climate change, as he and political rival Kamala Harris prepared to meet emergency workers in California.

"This is climate change, and this is an administration that's put its head in the sand," said Los Angeles Mayor Eric Garcetti, speaking on CNN's "State of the Union."

20 largest wildfires in California
The 20 largest Californian wildfires in recent history. Photo: AFP / Bertille LAGORCE

Trump plans to meet Monday with the heads of California's emergency services, battling history-making infernos that have now burned through nearly five million acres (two million hectares) across the US West, an area roughly the size of the state of New Jersey.

Harris, the Democratic vice presidential candidate who tweeted that Trump "denied evidence" the flames were "fuelled and intensified by the climate crisis," will also travel to California to assess the damage and meet fire officials.

US wildfires
A sign in front of a tent along the highway near Salem, Oregon on September 13, 2020 reads "Lost Everything Due To House Fire". Photo: AFP / Robyn Beck

Of at least 35 people killed by the blazes since the beginning of summer, 27 died this week alone. Dozens were still missing on Sunday.

Trump has made little comment about the blazes in recent weeks, but at a Nevada campaign event on Saturday he acknowledged the scope of the disaster.

US wildfires
Thick smoke from wildfires shrouds a highway between Portland and Mill City as blazes continue to burn in Oregon, destroying homes and killing multiple people this week. Photo: AFPTV / Eleonore SENS

"They never had anything like this," said Trump, who systematically downplays global warming. "Please remember the words, very simple, forest management."

Garcetti hit back, saying that "anybody that lives in California is insulted by that."

US wildfires
The Oak Park Motel's melted sign was destroyed in the Beachie Creek Fire in Gates, Oregon. Photo: POOL / Rob SCHUMACHER

"Talk to a firefighter if you think that climate change isn't real... This isn't about forest management or raking."

With battle lines drawn ahead of November's election, Democratic presidential candidate Joe Biden is also due to address the wildfires and their cause Monday.

US wildfires
A man stands guard with a firearm outside his home after wildfires and heavy smoke caused many of his neighbours to evacuate the area, in Estacada, Oregon on September 12, 2020. Photo: AFP / Robyn Beck

He recently called the threat of climate change "undeniable" and "existential."

Oregon wildfires
Oregon wildfires are visible in this NASA photo obtained September 13, 2020. Photo: NASA / Handout

Much of the West Coast remained coated in dense smog through Sunday, with Portland by a distance the world's most air-polluted city according to IQAir.

"It's apocalyptic," Washington state Governor Jay Inslee told ABC's "This Week."

US wildfires
The Bobcat Fire burns on a hillsides behind homes in Arcadia, California on September 13, 2020. Photo: AFP / Frederic J. BROWN

"It's maddening right now we have this cosmic challenge to our communities, the entire West Coast of the United States on fire, to have a president to deny that these are not just wildfires, these are climate fires," he said.

Most of the fatalities have occurred in California and Oregon, with emergency services in the two states recording 34 deaths.

US wildfires
A barn is shrouded in smoke on September 13, 2020 in Molalla, Oregon, which has been evacuated due to the Riverside Fire. Photo: AFP / Robyn Beck

More than 30,000 firefighters are battling the blazes, with officials warning that improved weather could end Monday as windier conditions return to the dry region.

Residents of Arcadia, on the outskirts of Los Angeles, were ordered to evacuate Sunday as the nearby Bobcat Fire spread south through forested terrain toward the metropolis.

Two new deaths were confirmed from the North Complex Fire, which swept at unprecedented speeds this week into areas already ravaged less than two years ago by the Camp Fire -- California's deadliest ever blaze.

"There are still active fires, power lines are down, trees are down, there are roads that are impassable," said Sheriff Kory Honea, warning evacuees it could take "weeks and weeks" to return to their homes.

Paul Clement described to AFP how he fled his home in Berry Creek.

"When I came around the bend, everything was on fire -- an entire hillside. So I ended up driving through and you couldn't see fifty feet (15 meters)."

"It was worse than the Camp Fire, which I didn't think was possible."

California has seen 3.3 million acres burn -- an annual record, with more than three months of the fire season still to come -- and over 4,100 structures destroyed.

Near the Beachie Creek Fire, east of Oregon state capital Salem, police had set up multiple road blockades on Sunday. Long lines of cars stretched in front of them, waiting in the thick fog to pass through.

Many were farmers trying to go home and feed their livestock.

"We went back to Mill City this morning, but police advised us not to as it is dangerous," resident Elaina Early told AFP. "The house is ok, but we leave now because the conditions are really not good."

"My son is six and he is in shock, it's hard for him," the 36-year-old added. "He keeps telling me, 'We live in a hotel now?'"

Preparations have been hampered by online claims that "extremists" are intentionally setting fires in Oregon, rumors debunked by the FBI.

Nearly one million acres of land have been torched in Oregon, double the normal annual amount, Governor Kate Brown said Sunday on CBS's "Face the Nation."

"This is a wake-up call for all of us, that we have got to do everything in our power to tackle climate change," Brown said.

Copyright AFP. All rights reserved.