Avalanche Forecast

Archived

Dec 16th, 2024–Dec 17th, 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, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Alpine and exposed tree line lee features are a suspect for the recently formed wind slabs.It is still early season conditions out there, thick to thin transitions within the snowpack are likely spots to trigger the deep persistent slab.

Confidence

Moderate

Avalanche Summary

Sunday's patrol to Mt. Kerkeslin did not notice any new avalanches. Saturday's Maligne field team reported cracking under skis 10m long on unsupported steep convex lee slopes but no natural avalanches were observed in the area.

Snowpack Summary

Friday-Saturday's moderate-strong winds blew the few cm's of new snow and available surface snow into isolated pockets of wind slab. The 7mm Surface Hoar that formed last week is likely flattened by winds but assume it could be preserved under a few centimeters of new snow in sheltered locations. An older buried surface hoar layer is found in sheltered alpine areas 40cm down. Lower down in the snowpack there are crusts with large faceted crystals above and below.

Weather Summary

Tuesday brings cloudy weather with sunny periods and isolated flurries. Trace of snow possible throughout the day. High of -9 in the alpine. Light SW ridge winds

Wednesday: Snow accumulation of 13 cm. Alpine temperature up to -5 C. Moderate SW ridge winds gusting to strong.

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

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.