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
Be on the lookout for changes in the snow as you transition into wind-affected terrain.
Use the terrain to your advantage in accessing the best and safest riding.
Summary
Confidence
Moderate
Avalanche Summary
On Saturday two larger natural avalanches, size 2.5, were observed. These were on southeast aspects and happened because of wind slabs. Explosive work produced avalanches up to size 2. They were able to trigger mostly wind slabs but were also able to trigger the persistent slab as well. Both should be expected to be reactive to human triggering for the time beingnow.
Snowpack Summary
Some areas of our region received a light dusting Saturday night. This will be sitting on wind slabs that vary in age created in the last 7 days by winds that came predominantly from the west initially and then switched to the southwest.
A buried layer of surface hoar sits 20 to 30 cm deep and remains a layer of concern, especially once a stiffer slab becomes established above it.
Generally speaking, we have a thin snowpack that has experienced a period of prolonged cold temperatures. The combination of the two has created a weakened snowpack by promoting faceting as a whole.
The overall height of snow is highly variable throughout the region with around 40 to 140 cm in the alpine.
Weather Summary
Sunday Night
Cloudy with clear periods, trace accumulation, wind northeast 8 km/h, -7 C at 1500 m.
Monday
A mix of sun and cloud, trace accumulation, winds northwest 12 km/h, -8 C at 1500 m.
Tuesday
A mix of sun and cloud, no accumulation, winds northwest 15 km/h, -6 C at 1500 m.
Wednesday
Cloudy with some sunny periods, 2 cm accumulation, winds northeast 15 km/h, -10 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.
- Be especially cautious as you transition into wind affected terrain.
Problems
Wind Slabs
Southwest winds continue to build wind slabs.
These slabs likely overlay a weak, sugary lower snowpack. If triggered, small avalanches may trigger a bigger avalanche by 'stepping down' to these weak crystals.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Buried layers of surface hoar and facets are still a concern as more load is added. Suspect triggering to be its highest in areas where the snowpack is shallower.
This layer will be most evident in sheltered areas at treeline, where surface hoar may be preserved, and in wind-loaded areas at upper elevations where a cohesive slab above has formed.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 12th, 2022 4:00PM
