Living in Colorado, one plague I dread every spring is the threat of dirty snow.
Blowing in from southeastern Utah, dirt poses two problems.
The first is personal danger, as dirt forms a weak layer and poorly bonds with newer snowfall, resulting in a sketchy layer buried in the snowpack as spring tours come into play. Simply put – dirt equals danger.
The second problem dirt causes is irregular melting and accelerated run off. Irregular melting forms sun cups which wreak havoc on spring corn cycles and have spawned an entirely new vocabulary with my friends. What was formerly thought of as buttercakes or reconstituted spring pow turns into frozen ocean and junkyard chunder. Ever had a ski partner go down with a broken rib from a fall on frozen chunder landing on their beacon? Not pretty, I can tell you.
Beyond the selfish context as a backcountry skier, dirt poses a much bigger issue than just personal safety. The Center for Snow Studies based in Silverton, Colorado has been focused on this problem for years, as it tracks to a much larger macro issue - that of climate change.
The dirt that blows in on the front end of Colorado storms in the form of apocalyptic billowing red clouds is at least in part due to the fact that the southwestern US has been under prolonged drought for years now. Climate models show we're likely to only see this increase as the planet warms, turning the southwest, eventually, into a dust bowl. While dust on snow has multiple causes (grazing, off road vehicle use, drilling impacts, agriculture), drought only exacerbates the impacts.
The kicker here is scientific research that culminated in a story in the Los Angeles Times by Eryn Brown (September 21, 2010), that shows dirt on snow reduces the amount of water flowing in to the Colorado River by a conservative estimate of 5%. What does 5% mean? 5% translates to over 250 billion gallons annually which equates to twice the amount of water a city such as Denver or Las Vegas uses in a year and equal to what Los Angeles consumes in 18 months.
Dirt also reduces snow’s albedo (reflectivity) by 30%, increasing melting by 50%. It’s akin to putting a black’80s concert t-shirt on during your next sunny spring tour. That rapid melt exposes surface vegetation earlier in the spring which consumes the runoff prior to reaching the river. Additionally, the faster decline of the snowpack negates the positive impact that traditional slower melts have in terms of cooling the atmosphere by reflecting heat.
So, next time you consider burning an old pair of rock skis as a tribute to the snow god Ullr add a few good words to keep the dirt away. And be sure to make good decisions, whether schralping pow in the backcountry with friends or in terms of consumption of plastic, energy and gas.
Penn Newhard is a Protect Our Winters Board member, Partner at Backbone Media and aspiring ski tech for his alpine racing kids.