Hello,
I wanted to pass on some snowpack observations from a trip into the upper St Mary's drainage in the southern part of the CAC's South Columbia forecast area.
There is about 40cm of storm snow overlying the variety of surfaces that were buried around Dec 28. The most notable is a layer of large surface hoar (2cm thick) that is present in the 1500m - 2000m elevation band. Yesterday this layer began producing small skier triggered avalanches as soon as the storm snow developed the slightest hint of slabbiness. There were a few natural slides in the size 1 range overnight and by the end of the day today there was a 40cm soft slab that could best be described as 'hair trigger'. Any open area would predictably fail and propagate with human weight and cause avalanches up to size 2 wherever the terrain was steep enough. Some of these were triggered from around 100m away.
Did not venture into the alpine due to poor visibility, but there were pockets of non-reactive windslab near treeline. Height of snow was 190cm at 2200m.
Heads up out there right now, that low elevation surface hoar layer could turn out to be a persistent problem.
Jeff Volp
SG
Kimberley, BC