Burning through the equivalent of 130,000 soccer fields, the Bootleg Fire, some 250 miles south of Portland, is the largest active blaze in the US.
A brutal start to the wildfire season in the western United States and Canada has worsened as a massive Oregon blaze exploded in dry, windy conditions and a new California blaze threatened communities devastated by the 2018 Camp Fire.
Wildfire officials raised their preparedness level to the highest tier – the earliest such move in a decade – and Canada's military joined evacuation efforts, as the region reels from the effects of consecutive heat waves that experts say have been worsened by global warming.
"This fire is going to continue to grow – the extremely dry vegetation and weather are not in our favour," said Joe Hessel, who is leading a team tackling Oregon's 227,000-acre Bootleg Fire.
Burning through the equivalent of 130,000 soccer fields, the Bootleg Fire some 250 miles south of Portland is the largest active blaze in the US, bellowing heavy smoke visible from space that is blanketing parts of neighbouring Washington and Idaho.
Firefighters have been dispatched from as far away as San Francisco to tackle the massive blaze, which is showing "extreme" growth through drought-affected brush and due to hot, dry and breezy conditions.
No serious injuries have been linked to the Bootleg fire, officials said, but it has destroyed at least 21 homes and 54 other structures, and forced an estimated 2,000 people from several hundred dwellings placed under evacuation. Many have taken refuge in a Red Cross evacuation center at the Klamath Falls fairgrounds. Nearly 2,000 homes were threatened.
The inferno is just one of around 70 large fires burning some one million acres (400,000 hectares) in the US alone.
California's Dixie Fire
The governor of the northwestern state of Montana on Wednesday declared a statewide wildland fire emergency.
And in California, the newly ignited Dixie Fire began ripping through land near the town of Paradise which was razed by the notorious 2018 Camp Fire – the deadliest in the state’s modern history, killing 86 people.
"The fire started just a couple of miles [away], on the same road, as the Camp Fire in 2018," David Little of the North Valley Community Foundation, set up to help Camp Fire victims, told the Los Angeles Times.
"It's really a sense of deja vu that's uneasy."
The Dixie Fire doubled in size overnight and was zero percent contained, but was moving away from populated areas such as Paradise.
Elsewhere in California the much larger Beckwourth Complex – a combination of two blazes sparked by lightning last week – neared 100,000 acres on Thursday.
Last year was the worst in California's modern history by acres burnt, but 2021 is currently outpacing even that record destruction. The fire season is starting earlier and ending later each year, while much of the state is in the grip of a severe multi-year drought.
Canada battles fires
Forest fires are also gaining ground across the border in Canada. The west of the country, which suffered an unprecedented heat wave recently, has reported 309 fires, 23 of which started in the last two days, according to local authorities.
One of the main outbreaks covers more than 10,000 acres (40,000 hectares) and nearly 900 homes have been evacuated.
Air quality alerts have been issued in many parts of British Columbia due to smoke from forest fires.
Scientists say heat waves arriving in the western US and Canada in late June would have been "virtually impossible" without human-caused climate change.
Human activity has driven global temperatures up, stoking increasingly fierce storms, extreme heat waves, droughts and wildfires.