Recent dust storm likely to impact spring runoff and backcountry skiing

“You can’t wax for dirt…”

One of the biggest “dust events” in recent memory to hit the valley took place Sunday night. The late afternoon and evening winds brought a covering of red dust that landed on the snow, cars, homes and anything exposed to the elements. According to the Center for Snow and Avalanche Studies, which monitors such dust storms, “Late Sunday afternoon [March 30] brought dramatic dust-laden southwesterly winds to southwest Colorado and beyond.”

While minor dust storms had tracked into the area earlier this winter, the Sunday event, with winds clocked on Scarp Ridge at more than 100 miles per hour, turned the landscape red, and backcountry skiers lamented the harm to spring skiing.
“Dust-on-snow events are generally a bummer for spring skiing,” said Crested Butte Avalanche Center forecaster Zach Guy. “The quality of skiing or snowboarding takes a downward spiral as dust emerges at the surface and starts to melt out. The beloved fast and smooth corn skiing becomes sticky with weird snowmelt textures. Skiing dusty snow is like playing Super Mario in the underwater levels. It is painfully slow.”
Guy said the dust actually has an impact on the avalanche situation in the local backcountry as well. “The dusty snow absorbs significantly more solar radiation than clean snow, causing rapid surface warming and snowmelt. This will cause our fat snowpack to melt out quicker than normal,” he explained.
“It also increases the frequency and speeds up the onset of wet avalanche concerns. So, from an avalanche perspective, anticipate that wet avalanche concerns will peak earlier than normal, so start earlier than normal on your tours. Skiing earlier also improves the quality of skiing, before it gets too sticky and slow. Dust layers can be problematic when they are buried by more snow; they can be reactive weak layers. Let’s hope the dust gets buried by lots of spring snow and doesn’t resurface for a while. However, if the dust does get buried, keep an eye on it. It can act like a persistent weak layer and be the culprit of slab avalanches.”
Chris Landry is the executive director of the Center for Snow and Avalanche Studies. It is based in Silverton but Landry spent most of last week observing dust layers around the state. “We just got back from a four-day, 1,200-mile lap around the state,” he said. “The Sunday evening event occurred on the last leg of our trip so we were ahead of this most recent event when we visited the Park Cone and Gunnison Valley sites. But, we know that it was a very major event in your area and much of the state.”
The center’s website (codos.org) explains, “drought and land-use activities are disturbing desert soil crusts and enabling dust emissions. The strong spring winds carry the dust into the atmosphere where it lands on mountain packs. The darker snow pack melts faster as it absorbs more of the sun’s radiant energy instead of reflecting it. This is causing rivers fed by the snowmelt to swell earlier, sending water downstream earlier in the spring.”
The Upper Gunnison River Water Conservancy District provides some financial support to the Center for Snow and Avalanche Studies, since dust can affect the timing of local water flows.
The center has been tracking dust events since the winter of 2004-05. The timing is pretty regular, in that April has recorded the most dust events, followed by March and May. The center refers to those three months as “dust season.”
“That period is also responsible for the final one-third of our average winter precipitation total, with the October-February period producing the balance. As a result, the vast majority of our dust, on average, has been deposited near the top of our snow cover,” the Center for Snow and Avalanche Studies website notes.
Guy says he has seen the last five springs be affected by dust events. “The last five years have seen a significant increase in major dust events. Dust deposition rates are five times what they were before human settlement. Land use and the current drought are both contributors to more dust available for transport during major wind events. Most of the dust originates from the Colorado Plateau. Boaters won’t be happy either, because dust generally shifts the peak flow of spring runoff several weeks earlier than normal, which means rivers are boney and drier than normal during the summer.
“When it comes to dust on the spring snowpack, you can’t wax for dirt,” Guy concluded. “I suppose another solution is to drive north.”