Lingering pockets of wind-drifted snow remain a concern for Wednesday at higher elevations. Seek out sheltered slopes and watch for reactive wind slabs around steep rolls and ridge features.
Recent southwest winds have drifted available snow into stiff wind slabs in lee and cross-loaded features at alpine and treeline. Natural activity may have subsided but human triggering remains possible.
Tuesday night: Clearing skies, isolated flurries, light west winds, alpine temperature -7 C, freezing level dropping to valley bottom.
Wednesday: Mix of sun and cloud, isolated flurries, moderate southwest winds with strong gusts, alpine high temperature -4 C, freezing level around 1500 m.
Thursday: Mix of sun and cloud, light southwest winds, alpine high temperature -1 C, freezing level around 1500 m.
Friday: Partly cloudy, isolated flurries, moderate southwest wind with strong gusts, alpine high temperature 2 C, freezing level rising to above 2000 m overnight.
Several recent natural, small to large (size 1-2.5) wind slab avalanches were reported on northwest through northeast aspects at upper elevations.
On January 16th, a natural, size 2 wind slab stepped down to the deep persistent basal facets below a rock band, details here.
Continuing west and southwest winds have formed stiff wind slabs on lee and cross-loaded terrain features at upper elevations.
A crust can be found up to treeline and on solar aspects in the alpine due to previous warming and sun exposure.
A well consolidated mid-pack overlies a generally weak basal snowpack. The bottom 10-20 cm of the snowpack consists of facets and deteriorating crusts. Although inherently weak, the benign weather pattern this week will likely promote a decreasing trend in reactivity for this avalanche problem. Areas that are most likely to harbor this problem are shallow, rocky start zones.
