Wildfires raged unchecked across parts of the western US today amid gusty and dry conditions, but forecasters said some weather relief was in sight that could help firefighters overwhelmed by the blazes.
In California, winds stoked unprecedented numbers of fires that have forced rescues and evacuations. In Washington, more hectares burned in a single day than firefighters usually see all year. Fires also forced people to flee in Oregon and Idaho.
A temperature plunge of as much as 15C, caused by a dramatic intrusion of polar air, helped slow wildfires in Colorado and Montana.
"The significantly colder airmass is helping reduce critical fire conditions across the West, however most of West coastline and adjacent counties have Red Flag warnings in effect for part of today," the National Weather Service said. A warning is issued when conditions combine to produce an increased risk of fire danger.
Diminishing winds were possible by tomorrow, "bringing some relief to the ongoing fires and fire weather threat," forecasters said.
A massive cloud of smoke covered much of California, dimming the sun to an eerie orange glow over San Francisco.
About 200km to the northeast, winds fanned a huge fire in the Sierra Nevada foothills and forced authorities to order early morning evacuations and warn other residents to be ready to leave.
The area is not far from the town of Paradise, where 85 people were killed by a fire two years ago, and Oroville Dam, where failing spillways forced a massive evacuation in 2017.
Yesterday, flames overtook 14 firefighters who had to deploy last-resort emergency shelters and destroyed a fire station in Los Padres National Forest on California's central coast. They suffered burns and smoke inhalation, and three were flown to a hospital in Fresno, the US Forest Service said.
Chris Barth, a spokesman on the Dolan Fire, said the three hospitalised firefighters were stabilised, with one in critical and the other two in fair condition. Barth said the firefighters' training and equipment had prevented a worse disaster.
Helicopters have been used in recent days to rescue hundreds of people stranded in the burning Sierra National Forest, where a fire has destroyed 365 buildings, including at least 45 homes. About 5000 buildings were threatened, fire officials said.
Flames threatened the foothill community of Auberry between Shaver Lake and Fresno.
In Southern California, fires burned in Los Angeles, San Bernardino and San Diego counties. People in foothill communities east of Los Angeles were warned to be ready to flee, but the region's notorious Santa Ana winds were weaker than predicted.
"We're encouraged that the wind activity appears to be dying down," Governor Gavin Newsom said. "The rest of the week looks a little more favourable."
After closing eight national forests in the southern half of the state earlier in the week, the US Forest Service closed California's 10 other national forests, citing "unprecedented and historic fire conditions throughout the state."
California has set a record with nearly 930,800ha burned already this year, and historically the worst of the wildfire season doesn't begin until the northern autumn.