Avalanche Forecast

Issued: Nov 25th, 2021 4:00PM

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

Avalanche Canada JSmith, Avalanche Canada

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New snow and strong southerly winds will likely form fresh wind slabs reactive to human triggers on lee features.

Extra caution recommended due to very limited snowpack observations at this point in the season.

Summary

Confidence

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

Weather Forecast

THURSDAY NIGHT: Cloudy with flurries; 3-5 cm / Moderate to strong, southerly winds / Low of -10

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

SATURDAY: Mix of sun and cloud with isolated flurries; 0-3 cm / Light, southerly winds / High of -10

SUNDAY: Mostly cloudy with flurries; 3-5 cm / Strong, southwesterly winds / High of -10

Avalanche Summary

New snow and strong southerly winds will likely form fresh 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

Moderate snowfall and strong wind over the past few days has likely formed pockets of soft snow in sheltered areas and wind slabs in lee terrain. While the snowpack depth is only 65 cm at Fraser, reports indicate more than 100 cm has accumulated at higher elevations. This means many upper elevation slopes have reached the threshold depth for avalanches. 

One or multiple crusts formed near the bottom of the snowpack in October, and the snow around these crusts has likely been forming weak faceted layers. These crusts and weak layers will now be buried 40-80 cm below the surface. While there have not been reports of avalanches on these layers, this structure is suspect and could develop into a bigger problem this season.

Terrain and Travel

  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Avoid freshly wind loaded terrain features.
  • Use ridges or ribs to avoid areas of wind loaded snow.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

Problems

Wind Slabs

An icon showing Wind Slabs

New snow and strong southerly winds will likely form fresh wind slabs reactive to human triggers on lee features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 26th, 2021 4:00PM