Winds produce dust on crust on Aspen slopes
April 4, 2014
An unwelcome spring guest arrived Sunday evening.
It blew in from the southwest late in the afternoon and created an eerie, dull-orange hue in the sky. It only hung around until sunset, but by then it had left a calling card.
Roaring Fork Valley residents awoke Monday to find a thin layer of dust covering vehicles that were left outdoors and on windows facing south. Skiers reported finding the same thin layer of ochre dust on the slopes, though not nearly as thick as it's been in past seasons.
Skier Erik Peltonen dubbed it "dust on crust," albeit a different kind of dust. "There's dirt under 1½ inches of new snow," he reported after leaving Aspen Mountain. "It's going to be interesting to see what happens when it warms up."
Overall, the conditions were good and "very skiable" despite the lurking dust layer, Peltonen reported.
An Aspen Times reporter said the red dust was widespread on Aspen Mountain and covered some exposures with a heavier layer of red dirt. Once the sun broke through and warmed temperatures, the snow softened up more rapidly, presumably because of the layer of dust.
"Great spring skiing, all in all. Just a little discoloration," the reporter said.
Corby Anderson, who does the video version of "On the Trail" for The Aspen Times, said skier Dale Dillingham, of Aspen, reported that the dust affected the upper half of ski area. Skiers aren't as surprised finding "snirt" or dirty snow at this time of the season, when high winds kick up dust in the Southwest, Anderson reported.
"The dust doesn't change the consistency of the snow much, other than the dust coloring the snow, which might attract more sun and make the snow melt faster," Dillingham told Anderson.
That's exactly the problem, according to the Center for Snow and Avalanche Studies, based in Silverton. The darker dust layer can shorten the snow cover by a few weeks, according to the center's website. High winds blow the dust into the atmosphere. It settles on the slopes and absorbs the sun's radiant energy into the snowpack, causing it to melt quicker. That can lead to higher streamflows earlier in the season, before it can be used for irrigation or stored in reservoirs, the center said.
The data on Sunday's dirt incident showed that the average wind speed was 39 mph in Silverton between 3 and 9 p.m. Sunday. The peak wind was 75 mph.
So far, Sunday's dust was the only significant layer deposited on the Aspen area's snowpack. In prior springs, numerous storms have left thicker layers of dust.