Dusty Snow

And how it handicaps water managers:

“I’m the snow guy who finds himself talking about the desert a lot,” says Derry, who directs the largest high-elevation network of dust-on-snow monitoring sites in North America, headquartered about 300 miles southwest of where he stands. “There aren’t many things we can do to tweak the supply side of our water, but one of them is mitigating dust to keep snow around on the surface longer.”

Worsening drought in the West’s deserts contributed to a heavy dust season on Colorado’s Loveland Pass this year, and the tea-colored snow shows it. Soil intermingled with ice crystals fell here on four occasions this spring. Subsequent storms buried each layer of dust particles under new snow. As the air warmed and the days grew longer, the snow melted and by June, the layers had combined at the surface. 

Snowfields covered in dust across the Rockies don’t just mar scenic views. The dirt acts like a blanket; the snowpack, no longer white, absorbs heat from the sun, melting more quickly and up to six weeks earlier than it would if there were no dust. Forty million people in the Colorado River Basin rely on sustained snowpack for drinking water and to irrigate 5.5 million acres of agricultural land through the hot, dry summer.