The wintry prairie fire that erupted along the Colorado waterfront was rare, experts said, but similar events will be more common in the years to come as climate change warms the planet – sucking it up. plant moisture – suburbs are growing in fire prone areas and people continue to start destructive fires.
“These fires are different from most of the fires we’ve seen in the West, in that they are grass fires and they happen in the winter,” said Jonathan Overpeck, professor at the School for Environment and Sustainability at the University of Michigan. “Ultimately, things will continue to get worse unless we stop climate change.”
The flames swept through grassy fields and drought-stricken neighborhoods northwest of Denver on Thursday at an alarming rate, propelled by guests up to 105 mph (169 km / h). Tens of thousands of people have been ordered to flee without warning.
“I walked out of Whole Foods, which is about a half mile from zero point, and felt like I had to jump in my car and rush for my life as the smoke, wind, and rain. nearby flames engulfed the area, ”Lafayette’s Susie Pringle said in an email. “It was scary!”
Three people were missing on Saturday and at least seven were injured, but no deaths were reported. Authorities estimated that nearly 1,000 houses and other buildings had been destroyed.
Many people whose homes were spared remained without power as temperatures dropped to single digits. The fire burned at least 9.4 square miles (24 square kilometers).
The cause of the blaze is still under investigation, but experts say it is clear what allowed it to spread so quickly.
“With snow on the ground, it absolutely wouldn’t have happened as it did,” said Keith Musselman, snow hydrologist at Boulder. “It was really the grass and the dry landscape that allowed this fire to jump long distances in a short space of time.”
Three ingredients were needed to start this fire: fuels, a hot climate and an ignition source, said Jennifer Balch, a fire specialist at the University of Colorado at Boulder. “And then you add a fourth ingredient, wind, and that’s where it turned into a disaster.”
Temperatures in Colorado between June and December were the hottest on record, Balch said. The grasses got thick because they had a wet spring, but saw no moisture until the flurries arrived on Friday night.
“All of Colorado is flammable, our grasses are flammable, our shrubs are flammable, our trees are flammable,” Balch said. “It’s a dry landscape that’s flammable for much of the year, and those times are getting longer with climate change. “
The lesson learned throughout this event is that “the interface between wilderness and urban areas is much bigger than we thought,” Balch said. This means that a larger area is at risk of forest fires.
This border area – where structures built by people meet unmanaged wilderness prone to fire – has always been the foothills, she said. Boulder firefighters consider the interface west of Broadway – a busy road that runs through downtown. But Thursday’s fire started east of that line, next to thousands of homes that have grown on the eastern side of the Rockies since the 1990s, Balch said.
“There were sections between Denver and Fort Collins that didn’t have development, but now it’s like a long track of continuous development,” Balch said. “And these houses are built with very flammable materials – wood siding, asphalt roofing.
“We have to completely rethink the way we build houses. “
The other big change is understanding how these fires start in the first place, she said.
“There is no natural source of inflammation this time of year. There is no lightning, ”she said. “It will either be infrastructure-related or human-made.”
“The way we live in the landscape and our daily activities make us vulnerable,” she said.
Over the past two decades, 97% of forest fires have been started by people, according to a recent study by the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder. The causes range from accidents on construction sites to a car with a hot exhaust pipe, to thrown cigarettes.
“I like to say, we need Smokey Bear in the suburbs,” she said. “We need to think about how our daily activities can contribute to ignitions or sparks that start forest fires.”
Unless people stop climate change by cutting back on fossil fuels, wildfires will threaten communities, Overpeck said.
“There is no doubt in my mind that the conditions for very bad wildfires, whether grass or forest, will only get worse,” he said.
As more people move to areas where forest fires occur, the threat increases.
“We are building cities and infrastructure so it’s only a matter of time before entire cities burn down like we had in California and events like this in Colorado.”
Associated Press reporter Brittany Peterson contributed to this report.
Martha Bellisle, The Associated Press
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