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 Wind Slabs and Persistent Slabs.
wlewis,
Avalanche Canada
Danger ratings have decreased but concern still remains for deeper weak layers and lingering wind loaded features.
Maintain your awareness as you transition through aspects and elevations.
Summary
Confidence
Moderate
Avalanche Summary
Over the last 3 days, activity has been limited to small human triggered slabs specific terrain features, mostly on west and northwest facing slopes.
During the storm last Friday, explosive control produced persistent slab avalanches that failed on the mid-Nov crust down about 50cm. No avalanches have been reported on this layer since - however it remains a concern.
If you head out into the mountains, please share your photos or observations on the Mountain Information Network. Your information helps us understand local conditions!
Snowpack Summary
Pockets of wind slabs have developed from northerly winds at higher elevations. Recent warm temperatures have likely created a widespread surface crust that may extend into the alpine.
A layer of surface hoar from early December is buried 30-50 cm deep below wind affected snow. This surface hoar remains a concern, preserved in shaded and sheltered terrain features. The primary concern within the snowpack is a crust buried in late November with weak facets sitting above, around 40-70 cm deep.
Total snow depths remain low for December with 90 to 140 cm at treeline and up to 200 cm in the alpine. Much of the below treeline elevation band is below the threshold for avalanches.
Weather Summary
An Arctic front dominates the weather for the next week. Light snowfall is expected Saturday night as a weak low south of Vancouver Island briefly competes with the arctic air.
Friday Night
Increasing cloud. Moderate westerly winds. Freezing levels drop to valley bottom.
Saturday
Mainly cloudy with isolated flurries. Alpine temperatures reach a high of -5 °C. Freezing level at valley bottom. Moderate to strong northwest winds.
Sunday
Around 5 cm overnight. A mostly cloudy day with another 5 cm possible. Light and variable winds. Alpine high of -15°C.
Monday
Mostly cloudy with light southerly winds. Temperatures drop further, expect a high of -20°C. Isolated flurries.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Wind slabs formed earlier in the week may still be reactive to human triggers. Expect to find these on west through south facing slopes, and may be poorly bonded to the crust below
Aspects: South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of facets and a crust sits 40-70 cm deep in the snowpack. This layer is most likely to be found in sheltered and shaded locations.
Small avalanches or large cornice falls could step down to this layer resulting in large, consequential avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 17th, 2022 4:00PM
