The lake’s drying up is having a bigger impact than scientists first thought.
The Great Salt Lake dust storms aren’t just affecting air quality in Utah. They threaten snowpack, water supplies and forests in the Wasatch Mountains.
A new study co-authored by three University of Utah scientists found that the winter of 2021-2022 was the dustiest on record in the Wasatch. And a whopping 23% of that dust load came from the Great Salt Lake.
“We’ve known in the past that we get dust from the dry lake bed, we can see it,” said McKenzie Skiles, assistant professor of geography and senior author of the study. “We knew we were going to see something. But I didn’t necessarily think it would be as important a dust source as it was.”
The U.S. research findings were published Thursday in the journal Environmental Research Letters.
The drying up Great Salt Lake has drawn public attention in recent years as a threat to the western ecosystem for migratory birds and to the health of millions of people on the Wasatch Front.
Dust also collects on the snow, making it darker. Darker snow absorbs more sunlight, speeding up the time it takes for it to melt. Scientists like Skiles can observe these layer cake-like deposits by digging holes in the snowpack.
“Something new is happening,” said Skiles, who has been measuring dust in Utah since 2009, “and it’s hard to tell from two years alone, but it seems we’re entering a new dust-on-snow regime.”
In the winter of 2022, the dark snow melted 17 days earlier than normal, the study found.
Faster flow is problematic because Utah’s reservoirs and municipal water supply systems are designed to accommodate more gradual melting. It’s shortening the state’s ski season — a multibillion-dollar industry — compounded by overall falling snow cover due to human-caused climate change. The earlier melting of the snow in the season also means that the mountain forests dry out faster in summer.
“You can imagine that the forests dry up in summer [them] more vulnerable to wildfires?” said Derek Mallia, research assistant professor in the Department of Atmospheric Sciences and co-author of the study.
Dry, stressed forests also make trees vulnerable to diseases, insect attacks, and dieback.
Mallia used storm and weather models to determine where the dust Skiles observed came from. About half, or 45%, came from the desert west of the Great Salt Lake. Another 17% came from dry lakes Sevier and Tule in southern Utah, hundreds of miles away.
“To an extent, dust on snow is a natural phenomenon,” Mallia said. “Any mountain area that borders a desert will have dust impacts.”
But the drying up of the Great Salt Lake, almost entirely man-made, has created a new, significant source of dust pollution.
“For snow reasons and 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 breathe it in.”
Despite this winter’s phenomenal snowpack, Skiles continues to see more dust than ever.
“It kind of surprised us,” Skiles said. “… From a purely visual point of view it was just as dusty, if not more dusty than last year.”
Although snow and rainstorms wet the dust sources on the lake bed and in the western desert, Skiles said, “As the storms subsided and dried up, the dust immediately increased.”
The dust also caused this year’s record-breaking snowpack to melt earlier than other years with heavy snowfall, data from the Utah Snow Survey shows.
However, that outflow caused the Great Salt Lake to rise five feet higher than the record low it reached in November. But scientists continue to watch dust blowing away from the bottom of the lake. Farmington Bay, which directly borders cities in Davis and Salt Lake counties, remains exposed.
“A 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 to life,” Skiles said. “I hope studies like this keep the pressure on our policymakers to protect the Great Salt Lake.”