[MCR] Rockies: Louise Falls slough/avalanche (Feb 16, 2011)

[Public Mountain Conditions Report]

Rockies: Louise Falls slough/avalanche (Feb 16, 2011)

I got a bit of a surprise today while leading the pillar on Louise  
Falls. A good-sized slough/avalanche rocketed over my head when I was  
about halfway up the pillar itself. As for size, it was probably only  
0.5 but had some force and definitely contained harder, larger chunks.  
It flowed primarily to my right (by a couple meters) but filled the  
back of my jacket and hood with snow. If I was a few body lengths  
higher and pulling onto the ledge, I bet it could have knocked me off.  
Once on top and in the trees, I discovered it had started from the  
shallow, treed gully directly above the route. I am unsure of the  
trigger (no sun and the afternoon snow squalls had not yet begun), but  
it had scoured the loose snow and looked like it took a couple of the  
snow mushrooms with it (hence the chunks). Despite being a small  
feature, the constant weekly storms must have loaded it enough to  
produce a loose snow avalanche.

It has traditionally been general consensus that Louise Falls does not  
have avalanche hazard above it (the walk-off descent definitely has  
avalanche hazard but that is a different story), however, many  
avalanche professionals have been surprised this winter already and  
this incident only adds to my concern regarding this winter's snowpack  
in the Rockies, particularly for ice climbers.

Sean Isaac
ACMG Alpine Guide