Dusting the snow on the Rockies

Two articles in High Country News and NPR recently on dust coming from Arizona and Utah, and even occasionally China that coats the snow in Rockies, making it darker, absorb more heat from the sun and melting faster. I suspect that the China link is a little overplayed, especially in the NPR story. There are large dust storms in China, and the NPR story offers a map to investigate it. But overgrazing and oil and gas exploration in dry deserts destroy where the fragile microbes that hold the soil together.

From the HCN story:

On desert grasslands that have never seen grazing, "there’s barely any
dust production, no matter what"; the dust traps she posts in those
areas collect perhaps a tablespoon every six months. Most years, traps
in formerly grazed grasslands collect about twice as much, and
currently grazed lands collect even more, about nine times as much.
But the most dramatic differences, says Belnap, emerge during severe
drought years. While the ungrazed grasslands stay more or less the
same, formerly grazed ground produces as much as 20 times the amount of
dust as in wetter years. Currently grazed lands "just go bonkers," with
the dust traps sometimes filling faster than Belnap and her coworkers
can empty them.