Avalanche Forecast

Archived

Dec 5th, 2023–Dec 6th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields.

The avalanche hazard has risen from Tuesday's storm plus rain at lower elevations destabilizing slopes in the short term. Make conservative decisions until the new snow has had time to settle and stabilize.

Confidence

Low

Avalanche Summary

A low elevation roadside avalanche size 1 near Parker's ridge released mid-storm touching the side of the road. Several storm slab size 1.5 noted. Visibility poor and limited to roadside but suspect natural cycle occurring at higher elevation. Temperatures were warm and precipitation was heavy rain or snow.

Snowpack Summary

Tuesday brought 30cm of snow with strong winds forming windslabs and storm slabs. This overlies a weak surface hoar layer or a thin sun crust on south and west aspects. Winds will continue to redistribute the storm snow at all elevations. The snowpack is 35-45cm in depth with a weak base.

Weather Summary

Tuesday night will be flurries, 8 cm of snow, -4 °C, light gusting moderate winds, and 1500m freezing level. Wednesday will be cloudy, flurries, 5 cm of snow, -3 °C, 1800m freezing level, and light west winds.

The Mountain Weather Forecast is available from Avalanche Canada https://avalanche.ca/weather/forecast

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Don't let the desire for deep powder pull you into high consequence 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.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.