Avalanche Forecast
Issued: Nov 27th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Loose Dry.
Conrad Janzen,
Another big storm will increase the hazard on Sunday. Expect natural and skier triggered avalanche activity to occur as the storm arrives.
Summary
Weather Forecast
Another significant storm arrives Saturday night. Forecasts show 20 to 40 cm of incoming snow by the end of Sunday with strong SW-W winds and freezing levels rising to 2000 m. Lower elevations will likely see some rain fall during the storm.
Snowpack Summary
10-30 cm of storm snow sits over a layer of wind hammered snow in the alpine. In some locations this new snow is not bonding well to underlying hard surfaces. The Nov 15 crust is 30-50 cm down and present up to 2100 m. The Nov 5 crust/facet layer exists near the ground. Snowpack depths at tree-line average 80-110 cm.
Avalanche Summary
One skier triggered size 2.5 occurred in the Lipalian area near Lake Louise on Saturday and failed on the basel facets. Several ski controlled or explosive triggered wind slabs up to size 1.5 were also reported by the local ski areas. No natural avalanches were observed however visibility was limited.
Confidence
Problems
Storm Slabs
With lots of new snow, strong winds and rising freezing levels we expect to see a storm slab form in many places that will be reactive to skier triggering and may fail naturally. Treat all steep terrain with caution as the new slab builds.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
With a significant new snow load over the next couple days we expect to see larger and more frequent avalanches occur on the basal crust and facets. These avalanches could start running full path so minimize your exposure to overhead hazards.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Dry
New snow and wind will result in lots of sluffing in steep gullies. If the snow turns to rain at lower elevations we could also see wet loose avalanches occur near valley bottoms. Not a good day to be traveling in confined terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Nov 28th, 2021 4:00PM
