Triggering wind slabs in steep, leeward terrain features may be possible at upper elevations. Monitor for these conditions where you travel.
Incremental snowfall and moderate winds are expected to form shallow wind slabs in lee features at upper elevations that may be possible to trigger.
Dry conditions for the next few days
Sunday night: Clearing overnight, isolated flurries with trace accumulations, moderate southwest wind, freezing level dropping to valley bottom.
Monday: Mainly sunny, light variable wind, freezing level rising to 1500 m and dropping to valley bottom.
Tuesday: Mix of sun and cloud, light southwest wind, freezing level rising to 1400 m and dropping to valley bottom.
Wednesday: Mix of sun and cloud, moderate west wind, freezing level rising to 1200 m and dropping to valley bottom.
On Saturday, operators reported ski cutting small (size 1) pockets of the recent storm snow. Observers also reported loose dry sluffs in the new snow in steep terrain. See this MIN report for an example.
During last week's warm weather, numerous small to large (size 1-2) wet loose avalanches released naturally on south-facing aspects up to 2000 m. In a shallow snowpack area east of the region near Apex, a large (size 2) slab avalanche released naturally on a weak layer of facets near the ground.
Last weekend, large explosives produced very large (size 2-3) results at Kootenay Pass. In thin snowpack areas on solar aspects, a few of these large avalanches are suspected to have stepped down to the January layer described in the snowpack summary.
Up to 15 cm of new snow accumulated over the weekend in favored areas while periods of moderate southwest wind formed shallow wind slabs in lee features at upper elevations. The new snow fell on a variety of snow surfaces including hard wind-pressed snow, a melt-freeze crust, or settled powder in sheltered, shaded areas. Additionally, a thin layer of surface hoar may also exist at this interface that could increase the likelihood of triggering wind slabs above.
Deeper in the snowpack, a persistent weak layer from late January is buried 80-150 cm deep and is composed of a combination of surface hoar, crusts, and facets. There is some lingering uncertainty about whether this problem remains reactive on isolated upper elevation slopes on solar aspects in thin snowpack areas.
As described in this MIN report, shallow snowpack areas in the east of the region may harbor a faceted basal snowpack. This structure can typically be managed by avoiding shallow rocky areas where the snowpack transitions from thick to thin.
