The large, controlled size 4 avalanches near Revelstoke last week are a stark reminder of the potential consequences when there is a really bad layer near the base of the snowpack. For those who may not have been skiing in Western Canada 19 years ago, here are a few pics of what can happen when weak layers, deep in the snowpack, are triggered. All are Class 4 avalanches. A few notes:
Pic A The whole valley is filled with debris.
Pic B The pickup truck gives scale.
Pic C The visible fracture is up to 4 metres.

Not saying this winter is the same but deep weak layers are sleeping dragons.