Bird’s Eye View of the Southwestern Snirt

Snirt (snow-dirt) is a bummer for skiers, but at least gives scientists an excuse for interesting studies (and perhaps associated grants). This year’s unusually thick layer of snirt in Colorado’s San Juan mountains is the result of a dozen “dust events,” meaning millions of pounds of dirt are scoured by the wind from the southwestern U.S., then deposited on the first major mountain range in their path.

 
Not only does snirt make for crumby skiing, but it acts as a solar collector and melts the snow faster (stating the obvious). Our spring and summer snowpack is a virtual reservoir that gradually releases water throughout the warm seasons, thus providing a steady flow for urban use and agriculture. If it melts too fast, well, we end up with floods early on then low flows in the fall — with possible water shortages.

What causes more snirt? I’d suspect over-grazing and perhaps development. It’s tempting to blame global warming as well, but scientists say “the present-day snow cover and hydrology of the American West have changed since the nineteenth century, independent of climate change… due to dust generated when the semi-arid landscapes of the western United States are disturbed by agriculture and grazing animals.” But, the credentialed brains do say that global warming is likely to exacerbate the problem. Sounds logical to me.

My take: If we get one more snirty spring that’s three in a row. That’ll convince me it’s time for us to change our normal annual spring spring skiing plans (we usually “staycation” around here) and be ready to do more traveling. The after/before photos below are from a NASA webpage on the subject.

By the way, over the years I’ve found that graphite wax works best for snirt.