| Yesterday we finished a week at Selkirk Lodge just southwest of Rogers Pass.
There has been well over a meter of snow in the past 10 days or so. This overloaded deep weak layers in the snowpack and as I'm sure most people have heard there was a major avalanche cycle mid-week with avalanches to size 3 in our zone and to size 4 elsewhere.
Since then things have settled somewhat. We skied almost exclusively at treeline and at that elevation in that zone we found two surface hoar layers down 120-150 cm that were unreactive to our tests, to skiing and to natural loading events. There were some windslab avalanches at treeline over the week after wind events, mostly size 1 with a few size 2s. We were able to ski some steeper terrain on moderate sized slopes with no overhead hazard from alpine terrain.
We made a few brief forays into alpine terrain but we kept to low angled slopes with little or no overhead hazard. This was where we saw evidence of large avalanches with most of them occurring on 35-45 degree slopes. Nearly all of them started around rocks or at the base of cliffs. The deepest fracture lines were perhaps 150-200 cm thick and those large avalanches seemed to have mostly been triggered by another, smaller avalanche that started higher on the slope.
Large, naturally triggered avalanche activity has tapered off but at the end of the week we still were avoiding steep alpine terrain as we had very limited information on what layer the large avalanches were failing on and how sensitive the instability was. Of note was that with probing on the Justice Glacier at 2100 m we felt a 50 cm thick facetted crust at the base of the snowpack and this was of concern to us.
The skiing was really good, with the best quality being found in the forest. Alpine areas have had a lot of wind effect. Mark Klassen Mountain Guide www.facebook.com/alpinism
|