Avalanche Forecast
Issued: Dec 15th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
TRettie,
Avalanche Canada
Use extra caution near ridgelines and "thick to thin" areas where the likelihood of triggering avalanches will be greater. The early December layer is starting to produce avalanches that could surprise experienced riders.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
Wednesday night: No new snow expected. Wind will be light to moderate from the Southwest. Low of -11 at 1600m.
Thursday: Up to 5cm of new snow with a high of -8 at 1600m. Winds becoming strong from the Northwest in the alpine.
Friday: no new snow expected. Moderate winds from the Northwest shifting to the Southwest. High of -13 at 1600m.
Saturday: a storm arrives bringing up to 15cm of new snow with strong Southwest winds. High of -9 at 1600m.
Avalanche Summary
On Tuesday one skier triggered size 1.5 storm slab was reported on a North aspect at 2200m. This avalanche occurred on the facets above the early December crust. The slab was 35cm thick.
Snowpack Summary
Up to 20cm of low density snow overlies old wind effected surfaces.
The defining feature of the snowpack is a widespread crust that reaches as high as 2400 m and now sits 30-80 cm below the surface. In many places overlying snow is well-bonded to the crust but in others weak faceted grains have been observed growing above it. The faceting is most prominent in the upper treeline where the crust is thinner.
Average snowpack depth at treeline is 200cm.
Terrain and Travel
- Be careful as you transition into wind affected terrain.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Wind Slabs
Isolated wind slab can still be found in exposed treeline and alpine features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
30 to 80cm of snow sits on the early December facet crust combo. a few people have been surprised by this layer over the last week. Use extra caution around "thick to thin" slopes, especially in the upper treeline.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Dec 16th, 2021 4:00PM
