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Avalanche Forecast

Archived

Dec 16th, 2024–Dec 17th, 2024

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Purcells, East Purcell.

Wind slabs are still possible to trigger in the alpine.

Avoiding large features and enjoying low-angle riding is a good way to manage a deep persistent problem.

Confidence

Moderate

Avalanche Summary

On Sunday, a small (size 1.5) wind slab was skier-triggered near the Bugaboos. It was on an east aspect in the alpine.

Snowpack Summary

10 cm of snow that has been redistributed by westerly wind sits on sun crusts on south-facing slopes and surface hoar in sheltered areas.

The base of the snowpack consists of weak, faceted snow over a crust from late October. This layer is a concern in the Invermere area and other similarly shallow snowpack zones.

Treeline snow depths are generally 50 to 70 cm, with deeper wind-loaded pockets in the alpine.

Weather Summary

Monday Night

Partly cloudy. 10 km/h west ridgetop wind. Treeline temperature -12 °C.

Tuesday

A mix of sun and cloud. 20 km/h west ridgetop wind. Treeline temperature -8 °C.

Wednesday

Mostly cloudy with 5 to 10 cm of snow. 15 to 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.

Thursday

Mostly sunny. 20 km/h southwest ridgetop wind. Treeline temperature -9 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be alert to conditions that change with aspect and elevation.
  • Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and slopes above cliffs.

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.