Triggering storm slab avalanches is possible. Watch out for signs of instability as you approach avalanche terrain.
Triggering storm slab avalanches is possible, especially in steep and convex terrain and near ridgetops that have been loaded by blowing snow during the recent storm. It is uncertain how well the recent storm snow bonds with the underlying facet/crust layers.
MONDAY NIGHT: Cloudy with clear periods, 40 km/h wind from the northwest, alpine temperatures around -4 C, freezing level at valley bottom.
TUESDAY: Cloudy, 30 km/h wind from the west, alpine high temperatures around -3 C, freezing level at 900 m.
WEDNESDAY: Cloudy with isolated flurries, light wind from the west, alpine high temperatures around -5 C, freezing level at 800 m.
THURSDAY: Cloudy, up to 10 cm of snow, 50 km/h wind from the southwest, alpine high temperatures around -5 C, freezing level at 1000 m.
On Monday, a few slab avalanches up to size 2.5 were triggered with explosives. They were up to 30 cm thick and released on a crust. On Sunday, numerous small natural avalanches (size 1) were observed. A few skier triggered avalanches of size 1-2 were reported. On Saturday, several slab avalanches of size 1-2 were triggered by skiers. Two artificially controlled avalanches of size 1 and 2 were reported. Some of the slabs were up to 50 cm thick and released on a crust. They occurred on all aspects. Avalanches of smaller size released within the recent storm snow.
The past week delivered about 15-60 cm of snow, with the highest accumulations around Kootenay Pass. This snow has been blown around by southwest wind and sits above hard layers of wind pressed snow and crusts. There are reports of several layers 30-90 cm below the surface that could develop into avalanche problems in the future. These layers could be composed of facet/crust layers or surface hoar depending on aspect and elevation. Several notable snowpack test results and avalanches were reported on these layers. Snowpack depths are about 120 cm at treeline and below treeline is just reaching threshold depths.
