Avalanche Forecast

Issued: Nov 27th, 2021 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is below threshold. Known problems include Wind Slabs and Persistent Slabs.

Avalanche Canada JSmith, Avalanche Canada

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Strong southwesterly winds have formed large wind slabs reactive to human triggers.

Persistent slabs may be possible to trigger on a crust near the bottom of the snowpack. See Mountain Information Network (MIN) report.

Summary

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

SATURDAY NIGHT: Mostly cloudy with isolated flurries; 0-3 cm / Moderate, southwesterly winds / Low of -14

SUNDAY: Snow; 5-10 cm / Strong, southwesterly winds / High of -11

MONDAY: Mix of sun and cloud / Strong, southerly winds / High of -10

TUESDAY: Cloudy with flurries; 3-5 cm / Strong, southwesterly winds / High of -10

Avalanche Summary

Strong southwesterly winds have formed large wind slabs reactive to human triggers on lee features.

With uncertainty about the snowpack structure, it may also be possible to trigger large avalanches from thin areas on big alpine slopes. Until there is more information about the snowpack we recommend an extra-cautious approach and careful snowpack evaluation, especially in high-consequence terrain.

Snowpack Summary

30+ cm of recent storm snow and strong southwesterly winds have formed thick wind slabs reactive to human triggers.

A persistent weak layer of facets over a crust near the bottom of the snowpack has been reported as being reactive to human triggers near Fraser. See MIN HERE.

Terrain and Travel

  • Avoid freshly wind loaded terrain features.
  • Use ridges or ribs to avoid areas of wind loaded snow.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

Problems

Wind Slabs

An icon showing Wind Slabs

30+ cm of recent storm snow and strong southwesterly winds have formed thick wind slabs reactive to human triggers.

Aspects: North, North East, East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A persistent weak layer of facets over a crust near the bottom of the snowpack has been reported as being reactive to human triggers near Fraser. See MIN HERE.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Nov 28th, 2021 4:00PM