Drying lakes are having a bigger impact than scientists initially thought.
Dust storms in the Great Salt Lakes don’t just hurt Utah’s air quality. They are threatening the snowpack, water supply and forests in the Wasatch Mountains.
A new study co-authored by three University of Utah scientists has found that the 2021-2022 winter was the dustiest on record in the Wasatch. And a whopping 23% of those powder loads came from the Great Salt Lake.
“We’ve known in the past that we were gathering dust from the dry lake bed, we can see that,” said McKenzie Skiles, assistant professor of geography and senior author on the paper. We knew we were going to see something. But I didn’t necessarily think it would be as important a source of dust as it was.
The US research was published Thursday in the journal Environmental Research Letters.
The drying up of the Great Salt Lake has attracted public attention in recent years due to the threats it poses to the western ecosystem for migratory birds along with the health of millions of people living along the Wasatch Front.
Dust also accumulates on the snow, making it darker. Darker snow absorbs more sunlight, speeding up the time it takes to melt. Scientists like Skiles are able to observe these layer-like deposits by digging holes in the snowpack.
Something new is happening, said Skiles, who has been measuring Utah’s powder since 2009, and it’s hard to tell for just two years, but it looks like we’re entering a new powder on snow regime.
In the winter of 2022, the darkened snow melted 17 days earlier than normal, according to the study.
Faster runoff is problematic because Utah’s reservoirs and municipal water supply systems are designed to capture a more gradual melt. It shortens the states ski season, an industry worth billions that is exacerbated by the overall decline in snowpack due to man-made climate change. Early season snowmelt also means that mountain forests will dry out more rapidly in summer.
You can imagine if forests dry up in summer, this does [them] more susceptible to fires? said Derek Mallia, research assistant professor in the Department of Atmospheric Sciences and co-author of the study.
Dry and stressed forests also make trees vulnerable to disease, insect epidemics and die-offs.
Mallia was able to determine where the dust Skiles observed was coming from by modeling storms and weather patterns. About half, or 45%, came from the desert west of the Great Salt Lake. Another 17% came from dry Sevier and Tule lakes hundreds of miles apart in southern Utah.
To some extent, the dust on the snow is a natural phenomenon, Mallia said. There will be dust impacts in any mountainous area near a desert.
But the drying up of the Great Salt Lake, which is almost entirely man-made, has created a significant new source of dust pollution.
For the snow and for us, for human health reasons, the Great Salt Lake is so close to us, Skiles said. If this is a dust source region, we will definitely breathe it.
Even with the phenomenal snowpack this winter, Skiles said he’s still seeing more powder than ever before.
It kind of caught us off guard, Skiles said. … Just visually, it was dusty, if not dustier, than last year.
Although snow and rain storms wet sources of dust on the lake bed and in the western desert, Skiles said, as the storms died down and dried, the dust lifted immediately.
The powder also meant that this year’s record-breaking snowpack melted earlier than other big snow years, data from the Utah Snow Survey show.
That runoff, however, lifted the Great Salt Lake five feet higher than the all-time low it hit in November. But scientists continue to observe dust rising from the bottom of the lake. Farmington Bay, which lies directly adjacent to cities in Davis and Salt Lake counties, remains exposed.
A good snow year didn’t fix the problem for us, and I don’t think we can rely on Mother Nature and good snow years to get the lake back up, Skiles said. I hope studies like this keep the pressure on our politicians to protect the Great Salt Lake.
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