BOULDER, Colo. — She was driving back to her home in the Colorado mountains on Saturday when she saw the ominous plume swirling into the sky. In an instant, Jyoti Sharp’s mind went back to 2013, the last time she had been forced out by nature.
Her home had been destroyed, as was much of Jamestown, the 280-person community where she lives. Then, the town had been wiped out by Colorado’s worst flood in a generation. This time, it was a swiftly growing wildfire at the end of a long and brutal season that had her packing to leave the house she had rebuilt and moved into just four months earlier.
“My heart was beating fast,” Ms. Sharp, 64, said of how she felt on Saturday as she recalled fleeing the flood with a single suitcase she happened to have packed for her son’s wedding. “My breathing was shallow. I had to keep reminding myself to breathe.”
The fire started on Saturday in the woodlands near Jamestown, a late arrival in a season that would normally be nearing its end but still rages in Colorado, straining firefighting resources to their limit and signaling for scientists another devastating consequence of rising temperatures in a changing climate.
Already, firefighters are battling to contain the Cameron Peak Fire, which has burned since August and grown into the largest fire recorded in Colorado history. On Sunday, it eclipsed 200,000 acres. And the latest fire spread rapidly, engulfing more than 8,000 acres by Sunday.
“It just exploded,” Mike Wagner, division chief for the Boulder County Sheriff’s Department, said in a briefing late Saturday. “It’s been so dry and just such high fire danger combined with lack of firefighting resources because of the number of fires not only in Colorado but across the West.”
Millions of acres have been scorched by wildfires in Western states this year, burning homes and businesses as they invaded communities and killed people who were unable to escape the flames. The fires have also showered ash upon communities beyond their direct path and cast a haze that darkened skies across the region.
In California, lightning storms ignited hundreds of blazes, some of which grew into the largest in modern state history. More than 8,500 wildfires have burned over 4.1 million acres in California, state fire officials said, killing at least 31 people. More than a million acres also burned in Oregon and Washington.
Dry conditions have also stoked what has become one of the worst years for wildfires in Colorado. More than 430,000 acres have burned so far this year, said Brian Buma, an ecology professor at the University of Colorado Denver.
Scientists say that wildfires have become hotter, more intense and more destructive in recent years. In Colorado, the threat has also intensified as the fire season has grown longer.
Typically, the state would see the arrival of mountain snowfall by October. Instead, there has been little to no precipitation in areas where the fires have burned. “It is very unusual for wildfires to start after October,” said Jennifer Balch, the director of the Earth Lab at the University of Colorado Boulder.
Scientists say that it has been an unsettling development, yet also one that has been anticipated as the region has been in the grip of drought and as temperatures rise globally.
“This is exactly what we expect from climate change,” Professor Buma said. “It’s not going to get any better — that’s the hard part. It’s becoming more and more regular, and that time in the fall when they can breathe a sigh of relief is being pushed out further and further.”
The dry conditions and powerful gusts of winds, reaching roughly 70 miles per hour, created a dangerous recipe for the rapid spread of wildfires. Thousands of people have been forced to evacuate.
The Cameron Peak fire ignited on Aug. 13 on the Arapaho and Roosevelt National Forests, northwest of Boulder. The fire traversed rugged terrain as it claimed more ground, making it difficult to contain for the more than 1,500 firefighters battling it. The fire is 62 percent contained, state fire officials said.
There was hope that a shift in the weather on Sunday could help the firefighters gain ground. “Watching the cold, calm and wet weather move in today — which was not in the forecast — I am grateful for answered prayers,” Justin Smith, the Larimer County sheriff, said in a post on Facebook on Sunday morning.
To the south, the East Troublesome fire had burned more than 12,000 acres and was just 5 percent contained by Sunday. The Williams Fork fire, which is also nearby, has burned more than 14,500 acres and is about 26 percent contained.
The fire that started on Saturday, known as the Cal-Wood fire for the name of an educational center near where it was ignited, had about 5 percent containment by Sunday afternoon, with about 250 firefighters mostly focused on protecting homes and other structures that could fall within its path.
It led to evacuations for Jamestown, which is only two miles from where the fire ignited.
The town, outside Boulder, was founded by gold miners along James Creek and is perched at about 7,000 feet in the eastern foothills of the Rocky Mountains. These days, it has become a bucolic mountain retreat with just one storefront business on Main Street, the Jamestown Mercantile — The Merc, to its regulars — serving as a community hub and pit stop for bicyclists.
With cartons still not unpacked from her return to her home in June, Ms. Sharp found herself quickly boxing up treasured photographs, and rings that had belonged to each of her parents.
Her partner, Mark Behan, was less concerned about possessions, recalling a fire at his family’s home as a child that nearly killed his brother. “It’s stuff that can be replaced,” he said. “Even if it’s a house, it can be replaced. People can’t be replaced.”
Still, an enduring question that arises in times of disaster is about the sustainability of living in the mountains, where the solitude and natural splendor can give way to danger.
“That will probably be in the forefront of my mind — for a few days until the nice weather comes back,” Ms. Sharp said. “It’s so beautiful up there.”
Charlie Brennan reported from Boulder, and Rick Rojas from Atlanta.