Avalanche Forecast

Archived

Dec 9th, 2024–Dec 10th, 2024

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.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

The new snow has created great ski conditions, but be cautious of wind-loaded pockets. Before entering steep or unsupported terrain, carefully evaluate both wind effect and the potential for triggering deeper instabilities.

Confidence

Moderate

Avalanche Summary

One natural size 2 avalanche, failing on the Oct 18 crust, and two natural size 2 windslabs were observed on southwest and south aspects on Monday, Dec 9 near the Icefields.

Snowpack Summary

Up to 25 cm of storm snow fell last weekend, settling on a newly buried weak layer. Below 2500m, this layer consists of a thin melt-freeze crust, while above 2500m, it is surface hoar in sheltered areas. Strong winds have redistributed the fresh snow into windslabs, which may fail either on the crust or on deeper layers.

Although three weak layers exist in the snowpack, the most concerning is the October crust which is found near the base with facets above and below.

Weather Summary

Tuesday

A mix of sun and cloud. Alpine temperature High -6 °C. Ridge wind from the west (10 km/h). Freezing level at valley bottom.

Wednesday

Cloudy with sunny periods and isolated flurries (trace amounts). Alpine temperature Low -7 °C and High -4 °C. Ridge wind from the west (10 km/h). Freezing level: 1600 metres.

Terrain and Travel Advice

Be mindful that deep instabilities are still present in the snowpack.
Be careful as you transition into wind-affected terrain.

Problems

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.

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.