Avalanche Forecast

Archived

Dec 18th, 2023–Dec 19th, 2023

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.

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 snowpack is weak, facetted, dry, and cold at all elevations, throughout the region. It's not a rider's snowpack; maybe not until after Christmas, or later. If you find the snowpack supportive, you are on a slab over weak facets, not a good combo.

Ice Climbers: What's over your head? Watch for isolated slabs, loose dry, and sluffs.

Confidence

Moderate

Avalanche Summary

Few small wind slabs observed in the last few days across the region. These slabs were found near ridge tops on northerly aspects and did not step down to deeper instabilities.

Snowpack Summary

The snowpack is 50-80cm deep and is weak and facetted. A surface hoar layer is down 15-20cm below 2300m. Strong winds have stripped exposed alpine and tree-line terrain and created wind-slabs in cross-loaded and lee features. Windward slopes are either stripped of snow or the snow left has been pressed into sastrugi.

Weather Summary

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

MondayCloudy with sunny periods and isolated flurries; only a trace. Alpine High -3 °C. Ridge wind light southwest. Freezing level: 1700 metres.

Terrain and Travel Advice

Avoid areas where the snow feels stiff and/or slabby.
Watch for newly formed and reactive wind slabs as you transition into wind affected 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.