Avalanche Forecast
Issued: Dec 11th, 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.
rgoddard,
Avalanche Canada
Much of our region has been wind-affected. Expect wind slabs of various sizes to be reactive to rider triggering.
A weaker layer further down in the snowpack is still reactive.
Avoid pockets of wind-loaded terrain and watch out for rocks exposed by the wind.
Summary
Confidence
Moderate
Avalanche Summary
On Saturday, reports of an animal triggering a natural size two avalanche were submitted from the northern part of our region. This avalanche was released on the weak layer created in mid-November. This was in the north of our area. Our neighbours even further north in Kananaskis Country reported evidence of reactivity of this layer on convex rolls. This same layer continues to be reactive in snowpack testing.
Local operators reported on Sunday that they were getting lots of reactivity from pockets of wind-loaded terrain. Many smaller wind slab avalanches were produced.
If you head into the backcountry, support your community by submitting a report to the Mountain Information Network. Thank you to those who have.
Snowpack Summary
Since Thursday night up to 20 cm has accumulated in some parts of our region. In the alpine and at the treeline strong westerly winds have moved much of this snow around. The new snow and new wind slabs are covering a variety of surfaces that they may not have bonded to yet. It is expected that the wind has built wind slabs upon wind slabs in some areas while in other areas the wind will have stripped away the majority of the snow.
Where the wind had less of an impact on the snow you can expect to find around 10 to 20 cm of soft snow sitting on 30 to 40 cm of more settled snow. Buried 45 to 65 cm down lies a weak layer comprising of surface hoar and facets. This layer has been shown to be reactive in snowpack tests and showed be kept on your radar for the time being. Further down the snow is sugary and faceted with a rain crust near the ground but this lower snowpack appears to be consolidating.
Total snowpack depths at treeline elevations are 75 to 155 cm.
Weather Summary
Sunday Night
Mostly cloudy, up to 7 cm accumulation, winds northeast 10 km/h, -10 C at 1500 m.
Monday
A mix of sun and cloud, trace accumulation, winds northeast 15 km/h, -8 C at 1500 m.
Tuesday
A mix of sun and cloud, trace accumulation, winds northeast 15 km/h, -8 C at 1500 m.
Wednesday
Mostly cloudy, 2 cm accumulation, winds west 10 km/h, -5 C at 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Caution around convexities or sharp changes in terrain.
Problems
Wind Slabs
Much of our region has been heavily wind-affected. Smaller micro features and cross-loaded terrain are expected to harbour wind slabs.
Small avalanches may trigger a bigger avalanche by 'stepping down' to the weak and faceted crystals buried deeper within the snowpack.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Buried layers of surface hoar and facets exist 50 to 75 cm down and are showing reactivity in snowpack tests. Avalanches on this layer are possible where a cohesive slab exists above it.
This layer could be triggered by a heavy load caused by a rider in shallow snow areas, on convex rolls, or by the weight of a smaller avalanche.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 12th, 2022 4:00PM
