Avalanche Forecast
Regions: Sea To Sky.
An uptick in northwest wind may form small new wind slabs to manage on Wednesday. Older, more stubborn slabs can already be found across many aspects in exposed areas.
Confidence
High -
Weather Forecast
Tuesday night: Increasing cloud and isolated flurries with a trace of new snow. Moderate to strong northwest winds.
Wednesday: Cloud and isolated flurries diminishing over the day. Light northwest winds. Alpine high temperatures around -17.
Thursday: Sunny, light northeast winds. Alpine high temperatures around -17.
Friday: A mix of sun and cloud. Light east or southeast winds. Alpine high temperatures around -17.
Avalanche Summary
With cold temperatures gradually robbing the upper snowpack of cohesion, observations from Monday show a trend away from wind slab releases and toward small loose dry avalanches triggering in steep start zones with skier traffic. A few more small wind slabs were still able to be triggered with ski cutting in the Whistler area on Tuesday.
Recent skier triggered wind slabs have been limited to size 1. Explosive control work conducted prior to the weekend produced size 2 cornice and storm slab avalanches.
Snowpack Summary
Wind slabs on a variety of aspects are likely beginning to facet and lose cohesion as a result of ongoing cold temperatures. Recent sun exposure has formed weak crusts on primarily south aspects.
Below the surface, 50-100 cm of snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1900 m, and a sun crust on south-facing slopes. There could be more than 100 cm on this layer in wind loaded areas.
A crust from early December, currently considered dormant, may be found around 200+ cm deep in the snowpack.
Terrain and Travel
- Carefully evaluate steep lines for wind slabs.
- Be aware of highly variable recent wind loading patterns.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avalanche Problems
Wind Slabs
Wind slabs may exist in atypical terrain features due to recent northerly wind direction. Although they tend to facet and lose cohesion in cold temperatures, wind slabs may remain sensitive to human triggers in steep convexities and near ridgetops.
Faceting and loss of cohesion in cornices can make them brittle and prone to fail. Give them a wide berth from above and below.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2