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Avalanche Forecast

Archived

Dec 3rd, 2023–Dec 4th, 2023

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Early Season
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Early Season
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Below Threshold.

Regions

Banff Yoho Kootenay, Little Yoho, Banff, East Side 93N, Kootenay, Lake Louise, LLSA, Sunshine, West Side 93N, Field.

Increasing avalanche hazard will occur as snow, warmer temps, and stronger winds promote wind transport and windslab development. This new snow is sitting on a very weak interface and sluffing is expected in steep terrain.

Ice climbers should be aware of what is happening above your chosen route.

Early Season Conditions persist.

Confidence

Moderate

Avalanche Summary

No new avalanches have been observed or reported for the last several days, but an increase in avalanche activity is expected.

Snowpack Summary

Increasing west wind and 5-10 cm of new snow is starting to form small wind slabs in steep lee terrain. These slabs sit over a variety of weak interfaces, including surface hoar, facets, and sun crust on steep solar slopes. The snow pack is still very thin and weak in most places with basal facets and depth hoar at the bottom of the pack. Snow depth ranges from 25-50 cm at treeline to 90 cm of total snow in the alpine.

Weather Summary

5-10 cm of snow are expected Sunday night with the largest amounts west of the divide. Monday will see cloudy skies and light flurries but only trace amounts of new snow. Ridgetop winds will remain strong from the west throughout the next few days. Treeline temperatures will range from lows of -12°C to highs of -5°C.

For more information click Mountain Weather Forecast.

Terrain and Travel Advice

  • Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.