Control burns ease wildfire risk but nearly impossible to do with red tape involved
Colorado’s snowcapped Rockies towered in the distance on a crisp April day as firefighter
Emilio Palestro used a torch to ignite damp prairie grass within view of a nearby farmhouse and
a suburban neighborhood.
Propelled by a breeze, orange flames crackled up a ditch bank, devouring a thick mat of dead
grass, cornhusks, and weeds. It was neither too windy, nor too humid, nor too hot — a rare
goldilocks moment for firefighters to safely clear irrigation ditches of weeds, grasses, and brush
that can block the flow of water and spread wildfire.
“At this time of year, it’s a race against what we call green-up,” said Seth McKinney, fire
management officer for the Boulder County Sheriff’s Office, as eye-stinging smoke curled over
newly emerging shoots of grass nourished by a wet winter. “We are threading that needle to find
the right time in between a rainstorm, red flag conditions” — when winds, temperatures, and dry
conditions magnify wildfire risk — “and snow melt.”
He’s trying to prevent conflagrations like the Marshall Fire, the most destructive wildfire
in the state’s history, which killed two people and incinerated 1,084 residences and seven
businesses in December 2021. That fire ignited in overgrown grasslands crisscrossed by
unkempt ditches, which together spread flames into urban areas with unprecedented speed,
according to scientific simulations and eyewitnesses.
The controlled use of fire by expert crews is widely considered the most effective way to reduce
the dangerous build-up of grasses and other vegetation that fuel larger conflagrations, experts
But it has become nearly impossible to conduct controlled burns like the one McKinney’s crew
set last month. A combination of overly-broad restrictions, erratic weather patterns, and public
resistance have left piles of dead branches and shrubs sitting in open spaces for months.
Figuring out how to overcome these barriers, prevalent throughout the West, is crucial to
addressing the fire risk, say land managers whose homes were also threatened by the Marshall
“We’ve done a lot of work in the forests about what to do to reduce fire risk and anticipate fire
behavior,” said Katharine Suding, a plant community ecologist at the University of Colorado
Boulder who is working to update fire modeling of prairie vegetation. “We need to do that in the
The restrictions and a burdensome planning process often postpone or indefinitely delay
controlled burns. Firefighters must complete multipart plans and comply with rules that can differ
in each of Colorado’s 64 counties. Large burns on federal, state, or county land require permits
from the Colorado Department of Public Health and Environment to ensure they don’t violate
federal clean-air regulations. And in some areas, burns are off-limits from November through
February because air pollution is already high.
The end result is that only a small fraction of what needs to be burned ends up being burned. In
2020, firefighters proposed burning 312,943 piles of branches and logs throughout the state but
were able to do only about 18% of that work, records show. Of 88 burns proposed to consume
vegetation across a large number of acres — in a forest or grassy area — only 55% were
completed that year.
Extreme weather and climate change also are getting in the way of executing prescribed burns,
documents obtained by ProPublica under the Colorado Open Records Act show. In 2022, a
prescribed fire driven by high winds and tinder-dry vegetation morphed into the largest fire in
New Mexico’s history, with devastating consequences for residents.
In Colorado, residents grew wary of controlled burns after one escaped in 2012 and killed three
people. The Lower North Fork Fire, near the foothill community of Conifer, burned 24 structures
and 4,140 acres. Afterward, prescribed burning ceased as state lawmakers enacted stricter
rules governing the practice.
Only about 1 in 1,000 prescribed burns spirals out of control, statistics show, but the ones that
do have added to public opposition.
The push-pull of fire prevention and community opposition could soon come to a head as the
U.S. Forest Service, Western governors, and Colorado counties ramp up prescribed burning to
rid overgrown forests and open spaces of a century worth of fuel, aiming to better protect
nearby communities. Federal fire simulations found 500,000 buildings could now be exposed to
wildfire in a single year.
Public lands managers hope to treat 50 million acres with controlled burns and mechanical
thinning in the next decade.
After Larry Donner, a retired fire chief in Boulder, and his wife purchased their house in 1991,
they installed noncombustible siding, double-paned windows, and a fire-resistant roof, and they
replaced a wood deck with flagstone. Still, it burned to the ground in the Marshall Fire. He
attributed the fire’s spread to poor maintenance of open spaces near communities.
“Thirty years ago, they mowed 20 feet around subdivisions, or they grazed and plowed
grasslands — then they planted houses, and they stopped,” he said, who gestured toward
grassy Davidson Mesa as he stood in front of his partially reconstructed Louisville home. “Fuel
reduction is a big thing for me. If you can keep fire out of neighborhoods, you can better protect
A New Understanding of Grassland Risk
Coloradans have always understood the threat of forest fires. The state ranks first among eight
Western states for the number of acres at high risk for fire, or “firesheds,” federal models show.
The Marshall Fire, however, made many residents realize that the state’s vast and populous
grasslands — abutting its largest metro areas on the eastern flank of the Rocky Mountains —
are also a wildfire threat. Cities from Fort Collins, in the north, to Pueblo, in the south, where
most Coloradans live, are surrounded by thousands of square miles of flat, open space that
evolved to burn every five to 15 years.
The fireshed around Boulder and the Arvada fireshed to the south are among the 10 most at-
risk zones from Wyoming to Nebraska, according to the U.S. Forest Service. Boulder ranked
41st in the western U.S. out of 7,688 such hazardous areas.
Around the Denver metro area, grassland acres outnumber forest acres, according to a first-of-
its-kind analysis conducted for ProPublica using wildland fire data compiled by federal agencies.
This spring, wildfires in grasslands and brush on the eastern slope of the Rockies, known as the
Front Range, have already forced evacuations and concert cancellations in suburban enclaves.
“The urgency of fire in the county, whether in the mountains or on the plains, is very real,” said
Boulder County Commissioner Ashley Stolzmann during a February meeting.
In the forests that blanket Boulder County’s foothills, residents are accustomed to smoke in the
air. Firefighters have burned vegetation there, primarily in the woods, since 1997. But for every
successful burn, there are just as many that don’t happen, public records obtained by
Each year, the Boulder County wildland team and the city of Boulder’s Fire-Rescue unit request
smoke permits — required when burns on public lands could cause air quality issues — from
the Colorado Department of Public Health and Environment’s Air Pollution Control Division.
Many are for county- and city-managed open spaces. Some foothill areas are grassy, like the
valley floor below.
The permits require contingency plans, notification of nearby residents, and analysis of the
vegetation and are approved only when winds are deemed less likely to send smoke toward
Burns aren’t allowed when the state issues air pollution emergencies or alerts for the area. And
the number of high-ozone days along the northern Front Range and in the Denver metro area is
increasing. The region is out of compliance with national air-quality standards.
Brian Anacker, senior manager of science and climate resilience for the city of Boulder, said his
community is “trying to accelerate our prescribed fire program.” But there are “barriers upon
barriers” that stop that from happening.
Regulations can also work at cross purposes: Winter weather often offers the lowest risk of a
prescribed burn getting out of control, but that’s also when smoke below 6,400 feet can most
affect the region’s poor air quality.
Firefighters and state air-quality regulators have begun experimenting with allowing burns in the
metro Denver area during winter months.
“We are starting to look for more and more of what we would consider off windows,” said Brian
Oliver, wildland fire division chief for the city of Boulder.
For example, Boulder County firefighters asked to burn up to 40 acres on Hall Ranch during
snow season using “additional experimental provisions.” These included burning between 10
a.m. and 4 p.m. on days when the air is clear, discussing the timing with the state meteorologist
and advising state air pollution staff at least a day in advance.
Firefighter David Buchanan last year asked regulators for permission to burn during the “high-
pollution season,” when it’s typically prohibited. He said that granting the permit would allow
crews to torch grassy areas and saplings when temperatures are low and there is more
moisture on the ground. Doing so would minimize smoke, he added, because fuels burn “swiftly
and efficiently.” State regulators granted the permit.
Boulder County’s challenges were echoed by federal watchdogs and Western governors. The
Government Accountability Office and state leaders this spring urged the Environmental
Protection Agency to reconsider regulations that curtail prescribed burning in areas that aren’t in
compliance with air quality standards.
Land managers told the GAO that these rules “could limit their ability” to rid high-risk areas of
vegetation, investigators said in a March report. The GAO added that controlled fires could lead
to less smoke overall because they help prevent future wildfires.
Both the rising interest in controlled burns and the difficulty in conducting them are apparent at
the state’s Division of Fire Prevention & Control. The agency, created after the escaped Lower
North Fork Fire, requires firefighters to complete a “prescription” that assesses 23 risk factors,
including how quickly fuels will burn, how likely the fire is to escape, how smoke can be
managed, and how far the fire is from homes and businesses.
Ensuring the public understands that there’s a detailed, scientific process behind prescribed
burning is key to gaining support for more controlled burns, firefighters and land managers
Also included in the prescription are optimal weather conditions, including a minimum
temperature for burns in grass and brush of 30 degrees and a maximum of 80 degrees; relative
humidity between 5% and 40%; and wind speed between 2 mph and 15 mph.
Such conditions are becoming rarer.
Snowstorms, fire weather watches, and red flag warnings — alerts sent out when dry air and
high, gusty winds create conditions that could rapidly spread fires — forestalled prescribed
burns this spring in the city of Boulder. Burning is prohibited when these warnings, issued by the
National Weather Service, are in effect.
Sometimes, all the conditions align: The U.S. Forest Service said in May it was able to burn
approximately 25,000 piles of dead vegetation this winter across the Arapaho and Roosevelt
national forests. The federal agency, along with other partners, also intentionally burned more
than 110 acres in this region this spring.
Grassland Wildfire Risk Foreshadowed in 2009
Residents on the valley floor in Boulder County remain leery of controlled burns, and many are
also angry at what they view as a lack of urgency to address the fire threat surrounding dense
“Our neighborhood is like a ship at sea in grasslands,” Collen Callin, a Superior resident whose
home survived the Marshall Fire, said following a March community forum attended by Gov.
Jared Polis and U.S. Rep. Joe Neguse, both Democrats.
“If they don’t mitigate them, I’m to the point that I get so stressed with winds I will probably
leave,” added Callin, who handed Neguse a flier that detailed how the blaze climbed from
grasslands onto wood fences that “created firebrands that were blown into our yards and caught
homes on fire.”
Land managers are urging patience. Officials are updating Community Wildfire Protection Plans
to weigh options for managing the fuels but warn the process will take a year to complete.
The last plan was made 12 years ago and acknowledged wildfire risk isn’t limited to
mountainous communities. “Plains residents are also at risk,” authors wrote, citing lessons from
the 2009 Olde Stage Fire.
In hindsight, that blaze was eerily similar to the Marshall Fire — severe winds and “large
evacuations of residents and their animals just after the holiday season.” But unlike the Marshall
Fire, it slowed as the winds died down, allowing firefighters to control it before it burned homes.
Still, it prompted planners to identify a “grassland wildland-urban interface,” though they didn’t
offer ideas to address the risk to communities on the plains.
The plan that’s being developed will have to address this issue, but the reality is the options are
few — mow, graze, or burn — and none are easy to carry out or guaranteed to be effective.
“We have 343 miles of agricultural property boundaries we manage,” said Stefan Reinold,
resource management division manager for Boulder County Parks and Open Space. “Are we
going to mow a 100-foot buffer twice a year? Is that really going to stop a fire — or are embers
going to make it into neighborhoods?”
Millions of dollars in state and federal grants are available for mitigation work on open-space
grasslands. At the March community forum in Superior, state officials were asked if they would
consider legislation to aid communities in deciding which methods are the most effective.
Lawmakers said they will discuss their approach this summer.
Firefighters would like prescribed burns to be part of the plan.
“Prescribed fire is the best way to keep grasslands healthy and vibrant,” Meg Halford, senior
forest health planner for Boulder County, said at a Jan. 30 town hall. “What is scary is that we
would do it behind your communities — not that it can’t be controlled.”
One day this spring, Buchanan, the Boulder County firefighter who’d requested out-of-season
burn permits, slapped out errant wisps of flame on a ditch bank with a “mud flap on a stick.” The
oddball device worked well to mop up the burn as Sheriff’s Office fire manager McKinney
described how he hopes to tamp down the stigma that surrounds prescribed fire.
His team would like to increase agricultural burning, which is exempt from federal smoke
management regulations. Doing more ditch burns would get residents more accustomed to the
sight of intentionally set flames and smoke, McKinney said.
“The goal is to normalize it so people can see the conditions are good,” he said. “And they know
we’ve had moisture recently and the winds aren’t high, so we must be lighting it for a reason.”
Fire Revealed Danger Posed by Ditches in Boulder County Suburbs
Like other climate-fueled wildfires, the Marshall Fire revealed new fire threats that have
emerged as the West heats up and dries out. Among them: the irrigation ditches that water
crops across the region and grow thick with trees, grasses, and other vegetation.
Until the Marshall Fire, Amy Willhite viewed vegetation in ditches just as an impediment to water
flows, not as a fire risk. That fact that overgrown ditches could help spread wildfire into
communities “was just a big shock,” she said, a senior water resources project manager who
until weeks ago oversaw the city of Boulder’s shares in about 60 ditches.
She and firefighters this spring walked unkempt canals as they began a first-ever
assessment of the risk they present.
A black-spotted woodpecker scolded overhead as Willhite reached a charred piece of prairie at
the end of a line of 21 sedan-sized piles of gray branches and brush. Here, firefighters had
begun a controlled burn of a mound in March, she said. They were forced to stop when the wind
blew smoke toward homes to the east.
“The plan was to burn them all,” she said of the piles. “It was really disappointing — there is
huge caution used when they do these things.”
It’s often not publicly known who owns the ditches — ownership is divvied up into hundreds of
shares that are tied to water rights, and shares are passed down among families — which
makes it difficult to pinpoint who is responsible for their maintenance. The records are not
public. Organizations that manage the canals, called ditch companies, are not required to
remove the fuel that they clear and stack alongside the ditches — often on land they do not
own, Willhite said.
As a result of these and other limitations, firefighters burned only a fraction of several ditches,
records obtained by ProPublica show, with the number of miles ranging from 3.21 (in two
ditches) in 2021 to 6.7 (in five ditches) in 2016 — out of about 113 miles of field ditches the city
maintains in collaboration with its agriculture tenants.
ProPublica is a non-profit newsroom that investigates abuses of power. Sign up for Dispatches,
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every week. This story was co-published with COLab, the Colorado News Collaborative.
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