Democratic politicians on the US West Coast have accused President Donald Trump of being in denial about climate change's role in the huge wildfires there, before his visit to California.
Blazes in California, Oregon and Washington state have burned almost 2m hectares (5m acres) of land and killed at least 35 people since early August.
Washington's governor called climate change a "blowtorch over our states".
Mr Trump, a climate sceptic, blamed the crisis on poor forest management.
The president is due to be briefed on Monday by emergency crews who have been battling the fires, during a visit to McClellan Park, outside Sacramento.
What's the latest on the ground?
Authorities in California, where 24 people have died since 15 August, reported on Sunday that firefighters were working to contain 29 major wildfires across the state.
They warned that the strong southerly winds and low humidity forecast for Monday could bring an elevated fire risk, and potentially have an impact on the North Complex Fire, which has scorched 106,000 hectares and is only 26% contained.
The US National Weather Service also issued a "red flag warning" for other areas of the West Coast, including Jackson County, Oregon, where the Almeda Fire has destroyed hundreds of homes.
The Oregon Office of Emergency Management said on Sunday that firefighters in the state were struggling to contain more than 30 active wildfires – the largest of which was more than 89km (55 miles) wide.
At least 10 people have been killed in Oregon in the past week. Officials have said dozens of people are missing and warned that the death toll could rise.
One person has died in Washington, where there were five large fires on Sunday.
What are the politicians saying?
Oregon Governor Kate Brown said her state was facing "the perfect firestorm".
"We saw incredible winds. We saw very cold, hot temperatures. And, of course, we have a landscape that has seen 30 years of drought," she told CBS on Sunday.
"This is truly the bellwether for climate change on the West Coast. And this is a wake-up call for all of us that we have got to do everything in our power to tackle climate change."
Washington Governor Jay Inslee described the situation as "apocalyptic".
"It is maddening right now that, when we have this cosmic challenge to our communities, with 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 told ABC.
The comments echoed California Governor Gavin Newsom's statement on Friday that the fires showed the debate about climate change was "over".
At an election campaign event in Nevada on Saturday, President Trump said he was praying for everyone throughout the West Coast affected by the wildfires.
But he insisted the blazes were "about forest management", which includes tree thinning and brush clearing.
"They never had anything like this," he said. "Please remember the words, very simple, forest management."
Mr Trump has previously called climate change "mythical", "non-existent", or "an expensive hoax" – but has also described it as a "serious subject".
He has decided to pull the US out of the Paris climate agreement, which committed the US and 187 other countries to keep rising global temperatures below 2C (35.6F).
What role is climate change playing?
BBC environment correspondent Matt McGrath says that while natural factors such as strong winds have helped the spread of the West Coast fires, the underlying heating of the climate from human activities is making these conflagrations bigger and more explosive.
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