Avalanche Forecast
Issued: Feb 6th, 2022 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
Avoid avalanche terrain at treeline where triggering a persistent slab is most likely. This layer can be remotely triggered, think about overhead hazard.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
Sunday night: no new snow expected. Moderate to strong southwest winds and a Low of -4 at 1500m.
Monday: light precipitation throughout the day bringing 5 to 15cm of snow with moderate west winds. freezing level around 1300m.
Tuesday: trace amounts of new snow with moderate to strong west winds and a high of -3 at 1500m.
Wednesday: sunny with no new snow expected. moderate northwest winds and freezing levels rising to 3000m.
Avalanche Summary
On Saturday a fatal avalanche occurred in the Duffy Lake area. This avalanche was a large, size 3, skier triggered avalanche with significant propagation. It was triggered in the upper treeline on a northeast aspect. It failed on a layer of surface hoar before stepping down to a crust from late January. A more detailed report can be found here. This layer was also responsible for a skier triggered size 2.5 avalanche last week in the neighboring Sea to Sky region.
Snowpack Summary
wind slab will likely be found on north and east aspects in treeline and above. A new crust will likely form below treeline as the freezing levels fall. This crust could also likely be found on south facing slopes in the alpine.
20 to 70 cm sits above a variety of surfaces including surface hoar, facets and a crust. This layer is most prominent at treeline and above. Especially in the Duffy area where it can be found on all aspects.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Remote triggering is a concern, avoid terrain where triggering slopes from below is possible
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
Problems
Persistent Slabs
20 to 70 cm of snow sits over a facet-crust weak layer combination that is possible to human trigger. This problem is particularly concerning in the Duffy Lake area. Recent observations demonstrate the potential for this problem to be triggered remotely and propagate far and wide. It can be found on all aspects at treeline and is most reactive at this elevation band but can be found above and below.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
rider triggerable wind slabs will likely exist on east and north aspects at and above treeline.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 7th, 2022 4:00PM
