Avalanche Forecast

Issued: Nov 30th, 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 swerner, Avalanche Canada

Email

Reactive wind slabs at treeline and in the alpine may exist on all aspects due to changing winds. 

Summary

Confidence

Moderate -

Weather Forecast

An onshore flow will bring mostly cloudy skies, new snow, and moderate to strong mountain top wind. Tuesday’s easterly wind will switch back to the southwest. 

Wednesday: New snow 5-10 cm. Alpine temperatures -12 C to -15 C and ridgetop wind moderate from the southwest.

Thursday: Light snow in the morning 3-5 cm. Alpine temperatures -15 C. Ridgetop wind generally light from the southwest. 

Friday: Trace of new snow. Alpine temperature dipping to – 22 C. Ridgetop wind light from the northeast switching to the southeast later in the day.

Avalanche Summary

No recent reports of avalanche activity on Tuesday. 

Over the weekend, large natural avalanches (size 2 and 2.5) were on alpine lee features. A MIN report also noted a slab release size 2 above Bryant Lake.

Lots of whumpfing and cracking have been notified across the region and are most likely to be associated with early-season shallow snowpack and wind-affected snow.

Snowpack Summary

Up to 5 cm of new snow fell overnight Monday. On most aspects above the treeline, wind-affected snow exists showing signs of cracking, whumfing, and cross-loading. Wind slabs are present and potentially reactive to human triggers. 

Little information is available about a weak layer of facets over a crust reported lower in the snowpack. Snow depths are approximately 80 cm at treeline and 100-120 in the alpine.

Terrain and Travel

  • Wind slabs are most reactive during their formation.
  • Avoid freshly wind loaded terrain features.
  • Approach lee and cross-loaded slopes with caution.
  • Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.

Problems

Wind Slabs

An icon showing Wind Slabs

Changing winds and light snowfall amounts may form touchy wind slabs on all aspects above treeline. Cracking and whumfing in the upper snowpack are indicators of wind slab. Human triggering is possible. 

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Dec 1st, 2021 4:00PM