Low hazard doesn't mean no hazard. Keep in mind that stubborn wind slabs may linger in isolated alpine features. Make note of the snow surface condition ahead of the next snowfall.
Previously strong winds deposited wind slabs on lee and cross-loaded features. Although triggering is unlikely, wind slabs may still exist in isolated areas in the alpine and in "alpine-like" features near treeline, particularly where these slabs sit on top of a crust/facet layer from early November.
Sunday night: Partly cloudy, light to moderate southwest winds, no precipitation, freezing level at valley bottom.
Monday: Increasing cloud, moderate southwest winds, no precipitation, alpine high temperature reaching -3 C, freezing level rising to 1400 m by end of day and a weak inversion setting up overnight.
Tuesday: Mostly cloudy, a short-lived overnight inversion is forecast to break down by morning, moderate southwest winds, scattered flurries with trace accumulations, alpine high temperature reaching -1 C, freezing level rising to 1500 m.
Wednesday: Mostly cloudy, light southwest winds, 5-15 cm of snow, alpine high temperature reaching -3 C.
At the beginning of last week's strong temperature inversion, small (up to size 1.5) loose wet avalanches were observed on steep solar slopes and in extreme rocky terrain.
There have been no reports of large avalanches in the past week. The most recent wind slab avalanche activity was reported at the end of November.
Over the weekend, observers reported widespread surface hoar growth (feather-like frost crystals). Check out these great photos from Coal Creek, Wranglers Cabin, and Harvey Pass. The formation and distribution of the surface hoar will be important to track ahead of the next snowfall. We appreciate the recent reports submitted to the Mountain Information Network. Keep them coming!
After several days of clear skies and warm air in the alpine, temperatures are returning to their seasonal normal, and melt-freeze crusts have been left behind on solar aspects. Strong southwest winds previously scoured upwind slopes and ridges and deposited snow into stiff wind slabs on lee or cross-loaded features. These old wind slabs may sit above a widespread rain crust from early November, which can be found up to 2500m and buried down 30-100cm.
Weak snow may be developing around this crust. However, given the stagnant weather pattern and decreasing trend in instability, this problematic snowpack structure is not currently listed as a problem. We can expect to see it transition to our problems page with the next snowfall. It will be a feature to monitor as the season progresses.
The snowpack is thin and variable in wind-scoured areas, and it tapers rapidly at lower elevations. Snowpack depths at sheltered upper treeline elevations are nearing 100 cm and beginning to exceed the threshold for avalanches.
