Tens of thousands of people have been evacuated and hundreds of homes have been destroyed as wildfires spread through the US state of Colorado.
The fast-moving fires are burning in Boulder County, north of Denver, and officials say deaths and injuries are likely as the blazes spread further.
Some 30,000 people in the towns of Louisville and Superior were told to leave their homes on Thursday.
Meanwhile, a state of emergency has been declared by Governor Jared Polis.
“This fire is not so much a question of resources,” he told a press conference. “This fire is a force of nature.”
“We hope that the winds die down, that the weather changes,” he added. “But for those who are directly affected, know that you don’t stand alone.”
Winds of up to 105 mph (169 kph) are sweeping flames across the region following a historic drought.
And while previous fires in Colorado have been in rural areas, these latest blazes are taking place in more suburban parts of the state.
At least some were sparked when power lines were toppled by strong winds, and they have quickly become the most destructive wildfires in the modern history of the state.
Some 370 homes went up in flames west of Superior and 210 were lost in the Old Town area of Superior, Boulder County Sheriff Joe Pelle said.
A shopping complex and hotel were also fully engulfed.
At least one first responder and six others were injured, Sheriff Pelle said, adding that more casualties were likely.
One video taken outside a supermarket showed a dramatic scene as winds ripped through the car park.
Patrick Kilbride, 72, was at work in a hardware store when he heard the order to evacuate, The Denver Post reported.
He rushed home but only had time to gather a few possessions before the flames engulfed the property. His pet dog and cat both died.
“It’s just a strange feeling to go from having everything to make your life comfortable to having nothing,” he said.
Colorado has been experiencing extreme droughts in recent years. Climate change increases the risk of the hot, dry weather that is likely to fuel wildfires.
The world has already warmed by about 1.2C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.