The Lee Fire burning in western Colorado is just two acres shy of overtaking the size of the 2002 Hayman Fire, currently ranked as the fourth-largest fire in state history.
The blaze, in other words, is shaping into a record-breaking fire during a record-breaking season. But new research illustrates that bigger, hotter, faster fires are just becoming the new norm.
All five of the largest fires in state history have taken place within the last 23 years. Of the 10 largest fires in state history, eight took place since 2012, with three in 2020 alone.
A new analysis from Colorado State University compiled data on wildfires in Colorado from 1990 to 2023 from the National Interagency Fire Center.
Ph.D. candidate in economics, Thomas Gifford, said the findings were stark: the average acreage for a single wildfire has increased to nearly 1,800 acres—up from 1,100 acres in the 1990s.
“Wildfires in Colorado are becoming more frequent. They're getting larger on average, and generally year to year, there's more unpredictability in the fire cycle,” Gifford said.
State climatologist Russ Schumacher said western Colorado is currently the epicenter of a deep, ongoing drought, which“set the stage for these big, fast-growing wildfires.”
Colorado only entered a new era of megafires in the last few decades. As of the late 1980s, Schumacher said the state’s largest fires on record were around 15,000 acres, a small fraction of the biggest fires currently burning across the state.
Some counties, including Larimer and Grand, have seen more than 15 percent of their total land area burned since the 1990s.
Gifford used fire perimeter data to select just for larger fires—to eliminate data on small backyard fires, or firepits—and because such records extended back to the 1990s.
“Back in the ’90s, Colorado had on average a dozen fires a year,” Gifford said. “But in the 2020s, the average number of total fires per year has increased to 72, about a sixfold increase.”
A small number of large fires have accounted for the vast majority of burned acreage.
Climate change is to blame
There are many factors for the growing size and frequency of wildfires, but scientists widely agree that the main reason is climate change.
The entire southwest has been in a megadrought for the past 25 years, the driest the region has been in 1,200 years. That has been compounded this summer in western Colorado by a seasonal drought, spurred by a deficit in snowfall that put the region in a drought heading into the hot summer months.
“These fires aren't just kind of dying out naturally,” said Kristen Boysen, managing director of the Colorado Department of Agriculture’s Ag Drought and Climate Office. “They're spreading very rapidly and they're getting very hot very fast.”
Boysen said it’s been a terrible year for Colorado ranchers, who’ve watched thousands of acres of rangeland burn. “That land will take years and years to recover,” Boysen said.
The drought has only deepened over the summer. Most of the Western Slope is now in “extreme” to “exceptional” drought, according to the latest U.S. Drought Monitor.
Schumacher said that the weather pattern is creating dry storms—no rain, just lightning. The lightning hits the dry kindling and grasses and ignites fires. Nearly every fire currently burning in the state was started this way. Many historic fires were often started by humans, so burn bans and restrictions were one way to stave off fire risk. Not so this year.
While previously the mega-drought was considered to perhaps be part of a natural cycle, researchers at the University of Colorado Boulder teamed up with colleagues in Miami, New York and Austin to publish a paper in the journal Nature directly linking it to human-driven carbon emissions.
Schumacher responded to their findings: “What this new paper is suggesting is that maybe the deficit in precipitation is also related to climate change and that it's more of a trend, rather than a cycle that's going to reverse at some point.”
The study looked at the Pacific Decadal Oscillation, a climate cycle that usually flips between wet and dry phases every 20 years. They found that instead, it’s been locked in a drier state for more than three decades—shrinking the Colorado River, parching farms and increasing the risk for wildfires.
“It's definitely getting worse and these droughts are getting more and more prolonged and our farmers and ranchers are really trying to figure out how to keep operating under hard conditions,” Boysen said.
The study builds on a canon of research linking increased fires to climate change. Previous research has found that the loss of groundwater is compounding droughts, which contributes to increased fire weather.
A history of fire suppression, rather than proper forest management implementing selective burning, is also responsible for larger, uncontained fires.
The lead author on the Nature study, Jeremy Klavans of CU-Boulder, said policymakers, water managers and farmers should brace themselves for continued drought.
“As long as humans continue to emit greenhouse gases at the pace we've been doing so … we should expect that the drought should continue for the next 10, 20, 30 years,” Klavans said.
These findings are supported by the state’s 2024 climate report, which states that “on average, fires have burned at higher elevations and with higher intensity than in the late 20th century. While several factors have contributed to these trends, rising temperatures are a major driver.”
A new threat this week: flash floods
After two months of extreme drought, monsoon rains are finally hitting the Western Slope. Burn scars are vulnerable to flash flooding, and with hundreds of thousands of acres exposed, fire management officials are bracing for floods and mudslides.
There’ve already been several small mudslides on the south side of the Lee Fire, closing County Road 5 several times this week, according to the National Weather Service in Grand Junction.
“It is just pretty alarming at how little precipitation there's been, really going back to February,” Schumacher said.
“Burn scars are very vulnerable to flash flooding if you get a burst of heavy rainfall. And we've seen that after the fires in 2020,” Schumacher said. Even moderate rainfall can cause flooding on the exposed soil.
