|Dust-ageddon in Crested Butte on March 30, 2014. Photo credit: Matt Hogan|
How will this dust on snow event affect snow stability and avalanches? Lets start with a key concept: albedo. Albedo is how reflective a surface is. White colors have a high albedo -- they reflect a high amount of radiation energy rather than absorb it. That is why you reach for a light colored T-shirt if you're going outside on a hot sunny day instead of a black T-shirt. Fresh snow has a very high albedo and it reflects most incoming solar energy. (So thats why my mom always made me double up on sunscreen when I went skiing!) On the other hand, the dark-colored dust more readily absorbs solar energy and heat, and also retains that heat longer.
|Pristine snow reflects radiation more effectively than dusty snow. Courtesy of Jeff Deems.|
|Snirt. Snow+Dirt. Photo taken March 31, 2014 near Crested Butte.|
|The crown of a large slab avalanche that was remotely triggered from hundreds of yards away last spring. It failed on a dust layer.|