Yesterday was a stunning, sunscreen-and-Capilene day on Lone Peak. The sun warmed the snow into fun creamy slush, commonly referred to as “corn snow’. Corn is characterized by large-grained crystals formed through repetitive melt-freeze cycles. When the temperature drops, corn snow hardens into an icy crust. As it warms, it transforms to a velvety texture that’s a dream to ski or ride.
As the temperature rises, this creamy corn can transform into dangerous slush and result in wet snow avalanches. In the most basic language, dry snow avalanches are caused when a dump overloads buried weak layers. Wet snow avalanches happen when the strength of the buried weak layers is decreased through melt.
Imagine corn snow crystals as grapes, and the vines are crystalline bonds between them. As the sun warms the snowpack, the “vines” transform into water. Now you just have a bunch of loose grapes floating in water. Add a slope and you get a wet snow avalanche, or “wet slide”. Surface tension is the property that holds molecules of the same liquid together (think raindrop). The surface tension of water will keep a slide from occurring until a certain point, when the amount of water percolating through the snowpack overpowers it.
When in the spring backcountry, beware of wet slides. The spring snowpack can transform greatly in short periods!!
At Griz, we’re still having a blast up at Big Sky Resort……BUT, we’re also pulling out our bike gear, and thinking spring. All winter clothing and last year’s spring/summer clothing is 50% OFF, and we have all sorts of deals throughout the shop.
