One fine afternoon last may, Jayne Belnap drove north out of Moab, Utah, in her beige Lexus SUV when the highway vanished. In an instant, a 100-foot-tall cloud of dust had swallowed up her vehicle. She wanted to brake, but she worried about another car slamming into her from behind. She tried to pull over, but she couldn’t see the shoulder. So Belnap split the difference: “I figured if I just crept slowly enough that I’d eventually get out of there or fall off the road.”
Luckily, the dust storm passed after a few minutes. But Belnap, who works at the U.S. Geological Survey and is the world’s foremost expert on the biological crusts that lock in desert dust, is well aware of the risks these tiny particles pose to people. In the 1990s a ranger at Canyonlands National Park in Moab, where she conducts fieldwork, broke her knee and two vertebrae in a collision caused by a dust storm. Dust affects denizens of the western U.S. in less dramatic ways as well. In the air, it can lead to respiratory problems, whereas dust settling on snowy mountaintops causes spring melts earlier in the season, harming agriculture in dry valleys.