Avalanche Forecast

High -

Some thin high cloud overnight with moderate easterly winds. Expect lows around -20. Clear and cold on Tuesday with light northerly winds and alpine highs around -15. Mostly clear on Wednesday with moderate-strong northeast winds. Cloud developing on Thursday with moderate westerly winds and a trace of snow.

On Sunday, pockets of wind slab released naturally and from explosives control up to size 1.5 on northeast aspects in the alpine. The most interesting avalanche recently was a size 2.5 slab avalanche triggered on an east facing slope on Mt Fernie. The slab failed on a cross-loaded treeline feature and ran full path. Although the exact failure plane is unknown, it points to the potentially touchy conditions on wind-affected features. A few days ago, a large (size 2) human-triggered avalanche was reported near Corbin in the Flathead Range in an area where wind had firmed up the surface snow and where sugary facets were present lower down in the snowpack. Evidence of a natural size 2.5 persistent slab avalanche was also noted on a treeline feature in the same area.

Up to 10 cm of snow was added to the snowpack Saturday night and Sunday. That means around 60cm of storm snow from last week sits above old hard wind slabs and spotty surface hoar. The cold weather in early December left several layers of weak surface hoar and facets buried 60-80 cm deep. These layers are more reactive in areas where the overlying slab gained cohesion with wind or settlement. A thick rain crust from mid-November is near the bottom of the snowpack and remains well bonded to the surrounding snow.