Saturday, April 05, 2014

Summit County dust storm could impact skiing and accelerate snow melt

#Breckenridge, Colorado.

Bill Linfield/Special to the Daily

Noticed any reddish-brown colors on the snow?
The dust storm that blew through Summit County earlier this week could have serious consequences for skiers, water managers and farmers.
The dust makes snow melt faster because the darker snow absorbs heat from the sun instead of reflecting it. Avid skiers and riders know well the slushy, crusty effects of snow melting on the slopes.
And toward the end of the season, said Chris Landry, executive director of the nonprofit Silverton-based Center for Snow and Avalanche Studies, “You end up skiing on mud.”
Depending on weather conditions in the coming weeks, the dust could cause the snow to warm and freeze in thicker layers, increasing the risk of avalanches, said Spencer Logan, avalanche forecaster with the Colorado Avalanche Information Center.
In 2006, dust storms in February contributed to a heavy-avalanche season, he said, with more than 100 slides in May that year. In 2012, though, the area experienced heavy dust but few avalanches.
“These dust layers will be something we’ll watch in the spring and summer,” Logan said.
Local officials also will monitor the potential for streams to surge with snowmelt early in the year, leaving less water for municipal and agriculture use later.
Sunday night’s storm reached Summit County and left patches of dust on the slopes Monday, which remained exposed until it started snowing Wednesday.
Another smaller dust storm Tuesday, which probably didn’t reach Summit County, was the fifth recorded this year.
The dust arrives from the Greater Colorado Plateau in a pattern that happens in Colorado every spring, said Landry, who has studied the dust for about eight years with the nonprofit center in Silverton.
Summit can expect more dust, he said, because the storms usually happen in March, April and May.
The reddish splotches at the resorts and the particles on your car likely blew in from eastern Utah, northeastern Arizona or northwestern New Mexico.
The color comes from iron oxide, a compound that Landry said isn’t known to cause water-quality problems. The dust also brings calcium, he said, which could be good for acidic waters.
The sun’s rays can still reach the dust if it’s only a few inches under a layer of fresh snow, Landry said, and layers of dust combine during the season to dramatically increase the speed of the snowmelt.
If the weather turns dry and stops bringing more snow to dilute the effect of the dust, streams could surge to extreme peak flows.
The Colorado mountains have been receiving this dust since the last ice age, Landry said, but evidence shows the size and frequency of the storms have increased since the mid-1990s.
“We’re into something entirely different than what was the case in the ’60s, ’70s and ’80s,” he said, but it’s unclear why.
Courtesy of the Summit Daily News.