CU researchers uniquely poised to measure Marshall aftermath, mitigate future disasters

Nearly one month after the Marshall Fire became the most destructive and one of the most unique wildfires in Colorado history, CU Boulder researchers from across campus-many of them personally affected by the fire-have pivoted and applied their expertise to the aftermath, hoping to learn from a tragedy in their own backyard and help prepare the country for the next "climate fire."

"What makes this fire really unique is that it happened in a community that is full of researchers that study this exact topic," said Natasha Stavros, director of the Earth Lab Analytics Hub at the Cooperative Institute for Research in Environmental Sciences (CIRES) at CU Boulder. "We are going to have measurements unlike anywhere else."

As a grass-fueled December wildfire in a crowded suburb, the fire was quite different than the state's massive forest fires of 2020, resulting in many novel impacts on the environment and human health. More than a dozen research projects are already underway, investigating everything from its impact on air and water quality, to the fire speeds that drove it, and how changes in infrastructure and insurance could limit damage from future fires like it. Researchers hope the findings can help inform homeowners, local governments and communities today and shape policies for tomorrow.

"In between all of us, there is so much expertise to address the causes and the impacts of this fire," said Joost de Gouw, CIRES fellow and professor of chemistry. "If we come together to produce and publish research, we can really change the future of how we think about wildfire."

Recipe for a winter wildfire

Three ingredients contribute to fire on the landscape: fuel, climate and ignition, said Stavros.

Due to higher-than-normal snowpack levels in late winter of 2021, a wet spring and a rainier than normal July, grasses grew abundantly in the Front Range throughout the year. By the time December rolled around, fuel accumulation was up 60% to 70% compared with a normal year. These plentiful dry grasses, combined with a 3-foot snow deficit and fierce Chinook winds, set the perfect stage that day for a spark to spiral out of control.

This abundant fuel would not have existed without increases in precipitation and snowmelt in the first half of 2021, followed by a drastic lack of moisture in the second half of the year-both of which point to climate as the driving cause.

"It's the first time in my career I have felt comfortable saying this is a climate fire," said Stavros.

Climate change will continue to have a hand in the future of wildfire, increasing the length and intensity of fire seasons as well as changing how, when and where water is distributed, said Stavros.

In addition to analyzing the impacts of fuel growth, researchers in the Earth Lab are also examining the role of another major factor in the Marshall Fiire: speed.

The Marshall Fire only burned 6,000 acres, less than half the size of Colorado's second most destructive fire in state history, the Black Forest Fire. Yet it tore through twice as much infrastructure, accounting for 39% of all homes lost to wildfire disasters in the state since 1999, according to Maxwell Cook, doctoral student in the Department of Geography and the Earth Lab.

The fire also now ranks in the top 15 most destructive wildfire events in the western United States, only one of two grassland fires in that list.

Cook is currently working with Jennifer Balch, director of the Earth Lab, to conduct research on the factors which make a fire most likely to burn down homes.

So far, their data shows speed matters most. This may seem obvious, but Cook, Balch and their colleagues have developed new data that now allows them to track and quantify that impact.

"The speed of the fire is also really what makes it difficult for emergency management personnel to respond, to get evacuation orders out in time," said Cook. "Management strategies that are aimed at reducing the speed of wildfires could be critically important for communities."

This could include creating fire/fuel breaks around suburban neighborhoods and removing vegetation next to homes-strategies already broadly in use in foothills communities around Colorado. Early detection systems and quick emergency responses are also key, especially in densely populated neighborhoods.

The Earth Lab is also involved in helping develop better maps of where homes are at risk of wildfire across the West, which can help communities and insurances companies better plan for and mitigate that risk.

"We may need to think hard about what we define as the wildland urban interface (WUI). There's a lot of flammable landscape and development out there that's maybe not accounted for," said Cook. "Building smarter, both in terms of where we build and how we build, that's going to be a big thing moving forward."

Clearing the air

Three weeks after the fire, homeowners and renters who did not lose their residences still face an important unknown: Is it safe to go home?

Buildings were inundated with smoke, full of unhealthy compounds created as the blaze burned paint, fried refrigerators and melted metals in nearby homes. These chemicals, absorbed by surviving structures like a sponge, now pose a previously unquantified problem.

Air quality scientists from CU Boulder, CIRES and NOAA quickly compiled an online resource about the impacts of post-fire smoke cleanup in homes. Led by de Gouw, they next installed instruments in several surviving homes to measure levels of harmful gases and understand the lingering effects of smoke on indoor air quality. Another team of scientists have also been driving through affected neighborhoods with a mobile laboratory to measure what the remains of buildings emit into the immediate atmosphere.

An interdisciplinary team including engineers, social scientists and chemists from across campus will continue to collect data indoors over the coming months to inform residents and local governments and learn more about lingering human health concerns that wildfires in urban areas can present.