Avalanche Forecast
Issued: Dec 16th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
trettie,
Avalanche Canada
Be aware that if triggered, avalanches may step down to deeper layers resulting in large, destructive avalanches. Keep your terrain choices conservative and be prepared to back off quickly if you find signs of instability like whumpfing and shooting cracks.
Summary
Confidence
Moderate
Avalanche Summary
Avalanche activity in the region has tapered off during the week. Over the last weekend the mid November surface hoar layer was very reactive throughout the region as well as the rest of the Selkirks and Monashees. This layer will likely remain rider triggerable in specific sheltered terrain features.
Snowpack Summary
Recent clear periods have formed largesurface hoar on sheltered slopes and a sun crust on south facing terrain. AS the winds change to a northerly direction it is likely that wind slab will be found on all aspects in exposed terrain at treeline and above.
A small layer of surface hoar from early December can be found down 30 to 40cm in sheltered and shaded terrain. On south facing slopes this layer is a thin crust.
A weak layer of large surface hoar crystals, facets and a melt-freeze crust from mid November sits 50-80 cm deep. This layer has been reactive at treeline between 1700-2200 m, on all aspects producing large remotely triggered avalanches.
Below the mid-November layer is a generally weak, faceted snowpack. Snowpack depths average 80-160 cm in the alpine.
Weather Summary
Friday Night
Cloudy with the possibility of light flurries bringing trace amounts of new snow. Moderate to strong northwest winds shifting to west in the morning with a low of -14 at 1800m.
Saturday
Scattered flurries bringing up to 5cm of new snow. Light to moderate westerly wind. High of -13 at 1800m.
Sunday
Scattered flurries bringing up to 5cm of new snow. Light westerly wind. High of -13 at 1800m.
Monday
Mostly cloudy with light flurries bringing trace amounts of new snow. Light southwest winds and a high of -15 at 1800m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Don't let the desire for deep powder pull you into high consequence terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
Problems
Persistent Slabs
There are now two persistent weak layers within the snowpack.
A 30 - 40 cm soft slab sits above a weak layer of surface hoar on shaded aspects and crust on steep solar aspects. Although natural avalanche activity has tapered off on this layer, human-triggered avalanches are possible.
A second weak layer of surface hoar and facets from mid-November is buried down 50 to 80cm in the region. This layer continues to catch professionals and recreationists off guard with numerous large human-triggered avalanches over the last weekend.
Read our featured blog to learn more about how to manage a persistent slab problem when traveling in the backcountry.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Northwest winds have likely redistributed snow. forming wind slab on southerly and easterly aspects and cross loaded others. New wind slabs could be more reactive where they overlie crusts, facets or surface hoar.
Aging wind slabs formed by previous southwest wind may remain reactive to human triggers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 17th, 2022 4:00PM
