The Great Salt Lake’s dust storms aren’t just harming Utah’s air quality. They’re threatening the snowpack, water supply and forests in the Wasatch Mountains.
A new study co-authored by three University of Utah scientists found the 2021-2022 winter was the dustiest on record in the Wasatch. And a whopping 23% of those dust loads came from the Great Salt Lake.
“We’ve known in the past that we’re getting dust from the dry lakebed, we can see it,” said McKenzie Skiles, an assistant professor of geography and senior author of the paper. “We knew we would see something. But I didn’t necessarily think it would be as important of a dust source as it was.”
The U.’s research was published in the journal Environmental Research Letters Thursday.
The drying Great Salt Lake has hooked the public’s attention in recent years due to the threats it poses to the West’s ecosystem for migrating birds along with the health of millions of people living along the Wasatch Front.
Dust also collects on snow, making it darker. Darker snow absorbs more sunlight, speeding up the amount of time it takes to melt. Scientists like Skiles are able to observe these layer cake-like deposits by digging pits in the snowpack.
(Otto Lang, University of Utah) Dust layers are visible in a snow pit at Atwater Study Plot in May 2022.
“Something new is happening,” said Skiles, who has measured Utah dust since 2009, “and it’s hard to say from two years alone, but it seems we’re entering a new dust on snow regime.”
In the winter of 2022, the darkened snow melted out 17 days earlier than normal, the study found.
More rapid runoff is problematic because Utah’s reservoirs and municipal water supply systems are designed to capture more gradual melting. It shortens the state’s ski season — an industry worth billions — which is compounded by declining snowpack overall due to human-caused climate change. Snow melting off earlier in the season also means mountain forests will dry out more quickly in the summer.
“You can imagine if forests are drying in the summer, does that make [them] more susceptible to wildfires?” said Derek Mallia, a research assistant professor in the Department of Atmospheric Sciences and co-author of the study.
(Matt Olson, University of Utah) Scientists McKenzie Skiles and Jewell Lund study dusty snow layers in 2019.
Dry, stressed forests make trees vulnerable to disease, insect outbreaks and die-offs as well.
Mallia was able to determine where the dust Skiles observed was coming from by running storm and weather models. About half, or 45%, came from the desert west of the Great Salt Lake. Another 17% came from the Sevier and Tule dry lakes hundreds of miles away in southern Utah.
“To some degree, dust on snow is a natural phenomenon,” Mallia said. “There’s going to be dust impacts in any mountainous area that’s next to a desert.”
But the desiccation of the Great Salt Lake, which is almost entirely human-caused, has created a new, significant source of dust pollution.
“For snow and for us, for human health reasons, the Great Salt Lake is so close to us,” Skiles said. “If that’s a dust source region, we’re definitely going to be breathing it in.”
(Photo courtesy of McKenzie Skiles, University of Utah) Dusty snow is visible at the Atwater Study Site in May 2023.
Even with this winter’s phenomenal snowpack, Skiles said she’s continuing to observe more dust than ever before.
“It kind of caught us off guard,” Skiles said. “... Just visually, it was as dusty, if not dustier, than last year.”
Although snow and rain storms wet down dust sources on the lakebed and west desert, Skiles said, “when the storms turned off and dried out, the dust picked up immediately.”
The dust also meant this year’s record-breaking snowpack melted out earlier than other big snow years, Utah Snow Survey data shows.
Chart by U.S. Natural Resources Conservation Service's Utah Snow Survey. The black line represents the 2023 water year snowpack, while the purple line represents previous record-high snowpack.
That runoff did, however, raise the Great Salt Lake five feet higher than the record low it hit in November. But scientists continue to observe dust blowing off the lakebed. Farmington Bay, which sits directly adjacent to cities in Davis and Salt Lake counties, remains exposed.
“One good snow year didn’t solve the problem for us, and I don’t think we can rely on Mother Nature and good snow years to bring the lake back up,” Skiles said. “I’m hoping studies like this keep the pressure on our policymakers to protect the Great Salt Lake.”
