Lucky us to have gotten snow relatively early this year all the way down to the valley floors. The skiing was deep this early December. The avalanche danger was a high 3 because the layer on the ground had turned to facets. This is not an unusual situation. It happens when we get early snow in the autumn then cold, dry weather afterwards. Because the ground is relatively warm, around -.1, and the air is cold, -15 in the alpine areas, this shallow layer of snow grows into faceted crystals that can’t support the weight of new snow. As the winter progresses, it gets covers with new lawyers of snow which eventually bond to each other and create a bridge over this weak ground layer. When we have a lot of snow, this bridge insulates our impact on this weak layer. So you’ll understand what the avalanche forecasters have been writing about these past two weeks:
These avalanche prone locations are to be found especially in little used terrain and at transitions from a shallow to a deep snowpack.
The WSL Institute for Snow and Avalanche Research SLF today
The weather forecast calls for sunny weather for another week, then possibly more snow and higher temperatures.
