Dust that settles on snowpack makes that snow darker, which absorbs more heat, speeding up snowmelt and runoff in the spring. Now, for the first time, a new study quantifies the impact of dust on snow across the entire Upper Colorado River Basin.
Using satellite data, the study found that over 23 years, the impacts of dust on snow were greatest in the central and southern Rockies, but no area in the Basin was dust-free. In high-dust years, researchers found that snowpack disappeared weeks earlier than in low-dust years.
McKenzie Skiles is a hydrologist at the University of Utah, and the director of the Snow Hydrology Research to Operations, or SnoHydRO, Laboratory. She was one of the lead researchers on the study.
“What we were expecting to see is that impacts would be dramatic in the southern Colorado Rockies because that's where we've been studying it and we knew,” she said. “But what we saw is that those impacts were relatively dramatic over the entire Colorado Rockies.”
“Dust gets up everywhere, everywhere dust impacts melts, but there is a lot of variability from year to year,” she said. “So there's no years without dust, but there's definitely years with bigger impacts, and one of the surprising outcomes of the study was that the dust impacts were actually greater in the first 10 years of the 23-year record that we looked at.”
There’s a lot of agriculture in the Colorado River Basin (studies estimate that around 75%, and as much as 80% of Colorado River water goes to irrigation for agriculture). Because it’s such a time dependent sector, with very specific growing periods and water requirements, Skiles said water managers need to take into account dust on snow.
“A lot of those areas are sort of depending on immediate runoff timing to get their water,” she said. “We should be accounting for this impact within our water forecasting models.”
She said there’s many factors that go into predicting snowpack levels: human-caused climate change, for instance, brings warming temperatures, changing precipitation patterns, and increased variability in the weather system. Adding dust into the mix makes things even more complicated.
“We don't know how all of those different parts are coming together,” she said. “But what we can say is climate change is something that's really big and complicated to tackle, but mitigating dust source regions, that's doable.”
She says modern-day dust levels that blow to the Rockies from the Colorado Plateau are higher than historical levels, due to increased grazing brought on by the white settlement of the West, and its disturbance to surface soils. That will mean conversations about land use on the Colorado Plateau to minimize soil erosion that causes dust.
“It can be as simple as just letting vegetation grow across the landscape and minimizing disturbance in areas that are particularly sensitive to soil erosion,” she said.
Skiles says that in order to get a better understanding of the dust on snow phenomenon, and understand its full impacts into the future, they need more real-time data and monitoring.
“One, putting out instrumentation to observe this impact in more locations,” she said. “So that includes not just the areas where we've been studying it in the Southern Colorado Rockies, but putting in instrumentation across the Colorado Rockies from North to South to monitor this impact into the future, and then also utilizing this satellite imagery, this remote sensing data that we've developed, to inform snowmelt modeling and hydrologic prediction in this area.”
Skiles said that due to federal programs and grants being cut, there’s a lot of uncertainty around funding at the university level, from continued funding on current projects to money for new work, like the projects she and her team hope to do coming out of this study.
“The uncertainty alone is really challenging, and there's not a clear picture of what our research is gonna be funded through in the future,” she said. “So, I find it always helpful to be hopeful that we'll be able to continue this research, but for now, we're not sure that we will be able to.”
Skiles said members of the public who live in the Upper Colorado River Basin and observe dirty snow in their communities should feel free to reach out to the SnoHydRO Lab to share pictures and information.
Copyright 2025 Rocky Mountain Community Radio. This story was shared via Rocky Mountain Community Radio, a network of public media stations in Colorado, Wyoming, Utah, and New Mexico, including Aspen Public Radio.
