Avalanche Forecast

Archived

Dec 6th, 2022–Dec 7th, 2022

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.

Early season conditions still exist throughout the forecast region. Ski with caution as the depth of snow is variable in all areas. Watch for signs of instability such as cracking and whumpfing; there is a persistent weak layer buried 25-35 cm below the surface. Sensitivity and consequence of this layer may increase with rising temperatures and increasing winds.

Confidence

Moderate

Avalanche Summary

On Tuesday, dry loose avalanches from extreme terrain were observed in the Maligne area up to size 1.5. Field team reporting settlements on a thick layer of preserved surface hoar below tree line in the Churchill range. Many hazards were still poking through the thin snowpack; their objective was aborted.

Snowpack Summary

Up to 10cm of new snow in the Maligne and townsite area; up to 5cm in the Icefields area. This new snow sits on variable wind slab up to 20cm thick in the alpine. Tree line and below there is a buried layer down 30-35cm that consists of surface hoar, facets, and sun crust depending on aspect and location. Snow depth ranges from 45-110cm.

Weather Summary

Wednesday expect a clearing and warming trend with winds increasing to moderate and strong values from the southwest. Additional flurries possible on Thursday. Cooling trend into the weekend with no significant precipitation in the forecast.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Recent wind has varied in direction so watch for wind slabs on all aspects.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.