Lingering wind slabs are the primary concern. Watch for denser, deeper drifts near ridge-crests and rollovers at upper elevations.
Incremental snowfall and moderate winds from the southwest have formed shallow wind slabs in lee features at upper elevations that may be possible to trigger.
Dry conditions and diurnal cycles for the next few days
Monday night: Mostly clear, light northeast wind, freezing level 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: Mostly cloudy, isolated flurries with trace accumulations light southwest wind, freezing level rising to 1500 m and dropping to valley bottom.
Thursday: Partly cloudy, light west winds, freezing level rising to 1500 m and dropping to valley bottom.
On Saturday, operators reported ski cutting small (size 1) pockets in 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, a large (size 2) slab avalanche released naturally on a weak layer of facets near the ground in a shallow snowpack area east of the region near Apex, .
The most recent avalanche observed on the late January persistent weak layer was reported February 28th, when large explosives produced very large (size 2-3) results at Kootenay Pass.
Up to 20 cm of new snow accumulated over the weekend in favored areas (Big White and Kootenay Pass). Periods of moderate winds from the southwest have likely 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.
