Layer of red dust could lead to early snowpack melt

“This is not helpful”

A big winter storm rolled through Crested Butte late last week, leaving behind some great powder to close out the ski season—along with a layer of thick red dust. The dusty layer on top of the snow could cause the remaining spring snow pack to melt off faster than usual due do a phenomena called snow albedo. While flooding isn’t much of a concern this year, the early runoff could mean bad news for ranchers and backcountry skiers.

Albedo refers to the reflectivity of a surface and how much solar energy it absorbs.
Pure, white snow reflects much of the sun’s energy back into the atmosphere. But a layer of dust on the top of the snowpack will cause it to absorb more solar energy and heat up faster, similar to wearing a black t-shirt on a sunny summer day.
Chris Landry, director of the Center for Snow and Avalanche Studies in Silverton, has been studying the effect of dust on snow for the past six winter seasons.
The layer of dust that fell on Friday, April 3 was the eighth dust event Landry’s team has tracked this season. Significant dust events also occurred in southwest Colorado on March 22 and March 29. Dust from the latest storm left a thin trace as far away as Boulder.
Landry says the dust is being swept up off of the Colorado Plateau and gets blown northeast toward the Rocky Mountains. He says dust events are more common in the spring and in the last six years of study the most significant dust events have always come after April 1. Landry says the April 3 dust event was a major one, and “almost certainly not the last.”
Some of the dust events are smaller than others, and scientists and frequent backcountry travelers can probably make out the different dust layers in a cross section of a study pit or ski cut.
But having such a large layer of dust at the very top of the snow pack can be troublesome, and not necessarily because of flood danger.
Upper Gunnison River Water Conservancy District manager Frank Kugel says the spring runoff is predicted to be average this season. The snow pack across the Gunnison Basin was at a below-average level up until last week. But the layer of dust could cause the annual runoff period to start earlier, and end earlier than usual—leaving less water available for use in the fall. “It may not bode well for ranchers, as it could cause a problem with irrigation demands later on,” Kugel says.
Landry agrees. “This is not helpful. Any one of the last three events would be problematic. The combination of the three will have a major impact,” he says.
That is, unless it snows more. Widespread dust events also occurred last spring, but they were followed by several significant snowstorms, which, Landry says, “put a lid” on the snow pack and postponed the serious runoff.
Without a good fresh snow cover on the layer of dust, Crested Butte Avalanche Center director Alan Bernholtz says the backcountry season could be several weeks shorter this spring. The dust doesn’t necessarily cause increased avalanche danger, but forecaster Billy Rankin says backcountry travelers heading out in the next few weeks should be aware of hazards like deep cups in the snowpack, exposed dirt and general late spring conditions.