What’s behind dirty snow? Researchers seek solutions for Colorado’s dust problems.

CORTEZ — On a snowy Wednesday in southwestern Colorado, about 70 researchers, soil scientists, water professionals, artists and more met to discuss one of Colorado’s dirtiest problems: dust on snow.

Each year, storms pick up dust from across the Southwest and drop it on Colorado’s mountain snowpack, where it influences how the snow melts. Its ripple effects impact water supplies, forecasts, irrigators, communities and ecosystems across the state. While the problem has become more clear, solutions are still elusive. This year, a collaboration of interdisciplinary problem-solvers set out to tackle the issue from as many angles as possible.

“This is impacting my community,” Jake Kurzweil, a Silverton-based hydrologist, told the gathering, recalling his thoughts as the project began this spring. “I could tell you what the impacts are. I could tell you how it impacts hydrology, but I have no idea how to fix it. We need to create a collaborative to do so.”

The collaborative consisted of 21 experts — soil scientists, hydrologists, artists, filmmakers, grant writers and more — who spent six months analyzing connections between land and water. The program was primarily organized by the Mountain Studies Institute, a nonprofit research institute in Durango, and the Wright-Ingraham Institute, a national nonprofit research institution founded in 1970 in Colorado Springs.

This Fresh Water News story is a collaboration between The Colorado Sun and Water Education Colorado. It also appears at wateredco.org/fresh-water-news.

On Wednesday, the experts shared their thoughts on the key questions they needed to answer to better understand the dust problem, and they explored ways to help solve it.

Dust on snow is a problem with widespread local and even global implications, presenters said during the meeting in Cortez’s Sunflower Theater.

After 20 years of tracking dust-on-snow events, researchers have found that there are no dust-free seasons, said McKenzie Skiles, an associate professor at the University of Utah. About 80% of the dust events happen in March, April and May, she said.

Dust layers can advance snowmelt by a month on average, or up to 50 days in extreme dust years. Scientists are still trying to understand what factors cause extreme years.

Over the past 20 years, research shows an increase in the frequency of low-concentration dust events. In the Four Corners area of Colorado, a decade of increasing dust emissions was followed by a decade of decreasing emissions.

“What if we’re able to do this big thing and lower dust emission amounts?” Skiles asked. “How does that benefit us all? What does success look like?”

What’s behind dirty snow?

One audience member from Telluride recalled seeing a red wall of dust rolling through the valley, causing her to leave an outdoor event because it was hard to breathe.

Jeff Derry, executive director of the Center for Snow and Avalanche Studies, recalled seeing bright snow fields turn rusty brown.

“The thing about dust, and I think you all agree, is it’s just very visceral. You can see it. You can feel it in your gut as to what’s going on there,” Derry told the gathering.

The dust that appears on Colorado’s snowpack is dropped by winter storms, which carry it from arid regions in Arizona, New Mexico and Utah. Some of that dust was loosened by human actions, like overgrazing and developing land.

Dark dust layers on the snow’s surface absorb more radiation, which causes the snow to melt faster and earlier in the season. When that happens, it changes how plants use water in the late summer. They send more moisture into the air, which reduces the amount of water entering streams and rivers, Derry said.

The 2024 water year — from Oct. 1, 2023, to Sept. 30 — was a typical year, Derry said. For the San Juan Mountains, which rise up just miles from Cortez, a typical year is pretty “nasty,” very dirty with significant dust deposits, he said. 

It’s pretty much impossible to forecast dust events, Derry said. Researchers are still trying to understand what factors create an extreme dust year versus a more typical year.

But the impacts of dust events can be felt far and wide. 

Bill Brinton, supervisor of the Mosca-Hooper Conservation District in Alamosa County, operates a small cattle grazing operation in the San Luis Valley. He gets his irrigation water from the Rio Grande River’s headwaters on the east side of the San Juan Mountains.

He feels dust on the snowpack is contributing to his region’s early runoff, which is happening about a month earlier according to state officials, he said. 

“I really need my water in May, June and July, and we’re seeing shortages even in years of good snowpack,” he said. 

New ideas from the “interdisciplinary problem-solvers”

The experts focused some of their work on understanding how communities can live with dust on snow, like how they can incorporate it into their water decisions. 

For example, the impact of dust events is still being incorporated into the models that guide water forecasting — like the ones that guide federal agencies who decide how and when water is released from Colorado River Basin’s biggest storage reservoirs.

The researchers are trying to improve those models by incorporating more dust-on-snow information. They’re looking at ways to grow and repair biocrust that stabilizes the soil’s surface in arid regions, use fungi to store water and repair soil, build wind fences at larger scales and incorporate Indigenous traditional practices. 

Leslie Sobel, a multimedia artist, explored ways to reach out to kids by creating new, educational lesson plans that include more information about dust on snow. 

Audience member Valerina Sampson, an artist and member of the Navajo Nation, lives near Shiprock on the Navajo Nation Reservation, which is part of the Southern Colorado Plateau, the primary source of the dust that lands in Colorado’s mountains. 

She has already tried to grow crops, flowers and other plants to help secure the soil, but the plant life struggled to thrive because of the low-quality soil. She wanted to have more discussions about other strategies they can use to improve vegetation and soils in her area. 

Len Necefer, CEO of NativesOutdoors and a member of the Navajo Nation, talked about forging clear connections between different factors — dust on snow, the Colorado River and winter vegetables grown in California — for lawmakers and voters. 

You need to be sensitive to the local impacts, Necefer said. In the 1930s, research-based federal policies tried to control grazing’s impacts on soil on the Navajo Nation by culling millions of sheep. The program helped with soil erosion, but it devastated the local economy, he said. 

“The question is, how much do we inform the voters?” Necefer said. “How much do we inform elected officials and get them to a level of understanding where informed decisions can be made in the context of history?”