The dominant theme of the past few days has been the wind, sustained SW moderate with strong gusts that have created windslabs in most exposed areas. Meanwhile, another 5-10 cm of snow is expected overnight, bringing Wednesday's storm snow total to 25-35 cm across the region. So, caution for windslabs and good powder below treeline.
As of Wed morning, four days of storm snow has accumulated to 25-35 cm across the region, combined with consistent moderate winds causing drifting and creating windslabs 20-40 cm deep in all exposed areas.
A layer of facets near the ground remains well established. In deep snowpack areas (western side), we have minimal concerns; our concern is mainly on the east side of the forecast area and especially in thin-to-thick snowpack transitions, where large, deep avalanches remain possible.
Both ski areas reported wind as the dominant theme, with explosives releasing size 1 hard slabs in exposed areas at both hills.
Another report from Rock Isle Lake near Sunshine of a remote triggered size 1, 30 cm deep on the Jan 2 surface hoar layer.
An interesting MIN report from Mt. Field on Monday showed a slab avalanche in the trees and we wonder if it might have run on surface hoar.
25-40 cm of storm snow has fallen over the past 4 days with continuous moderate SW winds forming fresh windslabs. In sheltered areas below treeline, this new snow sits on a layer of surface hoar buried on Jan 3, but this layer is not widespread, and no slab has formed above it yet.
There is 50-90 cm over the Dec 15 melt-freeze crust, which is present to 1800-2000 m, and 80-160 cm over the November facet/crust interfaces. In thinner snowpack areas, facets are present at the base.
A strong westerly flow is pushing moisture across our area, delivering more snow overnight before ending early on Wednesday. Expect another 5-15 cm overnight, with most falling on the west side of the Wapta Icefields. Temperatures will remain steady around -10, and wind speeds will fall slightly but remain in the moderate (wind loading) range.
