New University of Utah research has shown that the darkening of snow from dust is impacting snowmelt rates across the Colorado Basin, severely affecting the West's water supply.
Analysis of 23 years of satellite data has shown that dust-darkened snow speeds up runoff. This is the first study to widely map the impact of dusty snow. Researchers found that dust lowers snow's albedo (reflectivity); the darker dust covered surface absorbs more energy, thereby increasing the pace of melting. Dust speeds up melting by up to 1 millimeter per hour. In high-dust years, this translates to 10 millimeters daily. Dust-driven melting was shown to peak earliest and be the most intense in the at mid-alpine elevations in the Rocky Mountains.
The "dust on snow" effect is linked to the drying lake beds like those of the Great Salt Lake. For example, the high dust concentrations in 2022 accelerated snowmelt by 17 days and it was determined that the dried Great Salt Lake beds were the chief culprit.
