Avalanche Forecast

Archived

Dec 12th, 2022–Dec 13th, 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.

Despite limited avalanche activity, the snowpack structure is weak and caution is advised.

Confidence

Moderate

Avalanche Summary

Road patrol on the Icefields Parkway observed a natural size 1.5 avalanche in the alpine. This avalanche is estimated to have occurred a few days ago running on the persistent weak layer. Explosive control at Marmot ski resort at tree line and alpine has been producing small results mostly running within new snow and occasionally scrubbing to the persistent weak layer in the last few days.

Snowpack Summary

5-10cm of recent snow overlies previous wind slab in the alpine. At tree line and below a surface hoar layer can be found down 25-35cm in sheltered areas. The snowpack ranges from 40-100cm deep and can be unsupportive in locations.

Weather Summary

Tuesday will be cloudy with sunny periods and isolated flurries. Precipitation: Trace.Alpine temperature: High -1 °C.Ridge wind northwest: 10 km/h.Freezing level: 2000 metres.

Wednesday

A mix of sun and cloud with isolated flurries.Precipitation: Trace.

Alpine temperature: Low -12 °C, High -6 °C.

Ridge wind light to 15 km/h.

Freezing level at valley bottom.

Terrain and Travel Advice

Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

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.