Dust in the wind makes brown snow

SUMMIT COUNTY - Snow, especially newly fallen snow, is supposed to be white, right? After all, a big dump often inspires the poetically inclined to wax lyrical about the pure, virginal qualities of fresh fluff.

But that can all change if a storm is preceded by a wind event that delivers visible amounts of dust from drier climes. Such was the case Wednesday night, when strong south winds picked up fine-dust particles in Northern Arizona and dropped them all across the state of Colorado.

In some spots Thursday morning, the snow looked like it was tinted chocolate-brown, prompting calls from concerned area residents.

"It's pretty much statewide," said Ethan Greene, director of the Colorado Avalanche Information Center. "We've had reports from the San Juans, Winter Park ... all over."

Greene said exceptionally dry conditions in Northern Arizona contributed to the dust event, with a wind plume carrying the dust across most of Colorado.

Greene said the Copper Mountain ski patrol reported possible impacts to snow stability from the dust layers, with some easy shears occurring in the snowpack where new snow accumulated atop the dust.

There are several scientists in Colorado who study dust-on-snow deposition. Part of their research is focused on trying to determine whether growing deserts in some regions of the world are adding more dust to mountain snowpacks, whether that causes the snow to melt more quickly, and whether there are subsequent impacts to water supplies.

Greene said it's not unusual to see plumes of reddish dust from the desert Southwest drop on the Rocky Mountains in the spring, and said he has tracked dust plumes from deserts in Asia as they move across the Pacific and over North America.



Bob Berwyn can be reached at (970) 331-5996, or at bberwyn@summitdaily.com.