Avalanche Forecast
Issued: Dec 16th, 2021 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
We are reaching a tipping point where triggering large, destructive avalanches will become more likely . Where exactly these large avalanches can be triggered will be hard to predict. Read the forecaster's blog to learn more.
Summary
Confidence
Low - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
Thursday night: No new snow expected. Moderate Northwest winds in the alpine. Low of -15 at 1600m.
Friday: sunny and no new snow expected. Moderate winds from the Northwest shifting to the Southwest in the evening. High of -15 at 1600m.
Saturday: a storm arrives bringing up to 20cm of new snow with the greatest snowfall in the Monashees. Winds will be strong from the Southwest.. High of -9 at 1600m.
Sunday: some light snow in the morning. Strong Southwest winds in the morning becoming light West in the afternoon. High of -8 at 1600m.
Avalanche Summary
On Tuesday one skier triggered size 1.5 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 10cm 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 above it. The faceting is most prominent in the 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.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Persistent Slabs
A few people have been surprised by this layer over the last week. Use extra caution around "thick to thin" areas and on solar aspects, especially in the treeline.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Wind Slabs
Isolated wind slab can still be found in exposed treeline and alpine features.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 17th, 2021 4:00PM
