On December 30, 2021, the Marshall Fire destroyed more than 1,000 homes, damaged 149 homes, caused over $600 million in damage, destroyed and damaged dozens of commercial businesses, and killed two people in Boulder County.
In the following three years, experts have studied the conditions that led to Colorado’s most destructive wildfire — and whether another similarly destructive fire could happen again.
Researchers at the National Oceanic and Atmospheric Administration (NOAA) say a very specific set of circumstances allowed the fire to happen: a wet spring followed by a dry fall led to more dehydrated vegetation in the area than usual, and extremely high winds caused the fire to spread rapidly. (Fire investigators have determined that the fire was human-caused and have outlined several potential starting points).
Andrew Hoell, a researcher at NOAA’s Physical Science Laboratory in Boulder, says the fire was a very rare event, one that we’re not likely to see again, mostly due to the way wind moves in that specific area of the Front Range, a phenomenon called “mountain wave” winds.
But, he says, part of what can make fires like this one so destructive is where people have built communities.
“If there is a fire that begins, and there are winds on those days, this is a possibility, just because of how close those homes are built to the natural environment,” he said in an interview with Rocky Mountain Community Radio.
According to a 2023 Colorado State Forest Service study, over 2.5 million Coloradans live in the wildland-urban interface, or the WUI. Experts define it as an area where human infrastructure, like roads and homes, are built in close proximity to natural areas and resources that pose a wildfire risk. The study says more than 1 million residents in the WUI live in an area with moderate to severe wildfire risk.
Hoell says even though the Marshall Fire was unique, Colorado and other western states are still experiencing longer fire seasons.
“In terms of just warming temperatures, you're basically reducing the amount of time during the year in which you have cold temperatures, that you have snow on the ground,” he said. “So you're lengthening the duration of the fire season because of these warming temperatures, not just in Colorado, but really the general western United States.”
Snowpack and snowfall contribute to environmental conditions that can influence wildfire risk. Things like soil moisture and dry vegetation can significantly impact a fire’s severity or if it spreads.
“There have been several studies that have shown, whether it's by NOAA or in the broader scientific community, that increased aridification leads to a desiccation of vegetation that leads to fuels that help to facilitate fires, allow them to burn, allow them to spread,” he said. “So the science here is pretty clear in the sense that warming temperatures are very much a factor for increasing not only the area burned by wildfires but also the duration of the fire season as well.”
State agencies in Colorado, Utah, and Wyoming maintain maps that show how severe fire risk is for a given area. NOAA also has a program that focuses on forecasting, mitigating, and preparing for wildfires.
Copyright 2024 Rocky Mountain Community Radio.
This story was shared with KSUT via Rocky Mountain Community Radio, a network of public media stations in Colorado, Wyoming, Utah, and New Mexico, including KSUT.
