A blaze that erupted near the flashpoint of the deadliest wildfire in recent US history has headed away from homes but survivors of the 2018 blaze in the town of Paradise worry that history could repeat itself.
The Dixie Fire in northern California had burned a couple of square kilometres of brush and timber in Butte County and on Thursday moved into national forest land in neighbouring Plumas County.
There was zero containment and officials said people in the tiny, remote communities of Pulga and east Concow should prepare to leave at a moment's notice.
Flames raced along steep and hard-to-reach terrain about 16km from Paradise, the foothill town that was virtually incinerated by the Camp Fire that killed 85 people.
Larry Peterson, whose home in neighbouring Magalia survived the previous blaze, said some of his neighbours were getting their belongings together in case they had to flee.
Other locals stocked up on water and other items.
"We pretty much left with our clothes on our backs" during the previous fire, said Jennifer Younie of Paradise.
"So this time we are looking to be more prepared and more vigilant."
The blaze is just one of nearly 70 active wildfires that have destroyed homes and burned through more than 4000 sq km in a dozen mostly western states, according to the National Interagency Fire Center.
In southern Oregon the Bootleg Fire, the largest wildfire burning in the US, had torched an area larger than New York City and destroyed 20 houses.
It threatened 2000 structures in an area that has been gripped by a historic drought.
The National Weather Service tweeted late on Wednesday that a "terrifying" satellite image showed gigantic clouds fuelled by smoke and hot air had formed over the fire - a sign the blaze was so intense it was creating its own weather, with erratic winds and the potential for fire-generated lightning.
Extremely dry conditions and heat waves tied to climate change have swept the region, making wildfires harder to fight.
An extreme heat wave late last month sucked vegetation dry in the Pacific northwest, where firefighters say they are facing conditions more typical of late summer or autumn than early July.
The Northwest Interagency Co-ordination Center moved the region up to the highest alert level on Wednesday as dry gusts were expected in some areas and new fires popped up.