Scientists say it’s being caused by a variety of factors, such as more frequent windstorms and droughts, as well as the way the land is being used.
Researchers from the University of Colorado Boulder say the dust clouds can reduce air quality and visibility, and in the worst cases, force highways to be shut down.
A massive dust storm passing over Interstate 80 near Winnemucca, Nevada, on Monday caused a 27-car pileup that killed at least one motorist.
Such clouds of dust and sand are also changing the chemical makeup of the soil across a wide area.
Older people who have grown up in the West have long complained that dust storms are becoming more frequent than decades ago.
But there had been no direct scientific evidence to prove it until recently.
While dust has never been systematically measured, calcium in rainwater has. The mineral can be whipped up into clouds during dust storms, and researchers found it had increased in rainwater at 116 of 175 monitoring stations.
The increase was especially focused in locations across Colorado, Wyoming and Utah. The dust has also fallen on the snowpack across the Rockies, with the dark particles absorbing more sunlight and causing more snow to melt.
Photo: Mike Olbinski