21 Dec 2011

Not much to talk about as far as avalanche activity, so I thought we could discuss a misleading term that is open for interpretation. Rotten is used when we are describing crusts or old facets in the snow pack. Looked up the word rotten in several dictionaries and in the context of life sciences the definition is decomposing or decaying. Another definition is breaking up, especially through age or hard use. Earth sciences refers to it as soft or crumbling.
From Mountaineering, Freedom of the Hills, they have there own interpretation, "Rotten snow is a spring condition characterised by soft, wet lower layers that offer little support to the firmer layers above. Rotten snow forms when lower layers of depth hoar become wet and lose what little strength they have. It is a condition that often leads to wet loose-snow or slab avalanches running clear to the bare ground."

In the avalanche community we use the term often when we describe the old loose facets around rocks or when a crust starts to break down and we refer to it as rotting. I am sure you have read the avalanche bulletins and the word rotten has come up on many postings.

So, when we have decomposing stellars with lots of skier traffic do we have rotten snow?

At 06:00 Hrs the temperature at the Horstman Hut was -13 with light winds. The ridge will break down again on Friday.  The weather models are all trending to powder on Christmas Day.