Avalanche Forecast

Archived

Dec 26th, 2022–Dec 27th, 2022

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 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, human triggered possible.

Regions

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

Up to 30 cm of new snow in combination with strong winds and a warm temperatures are a true test of our weak, faceted, snowpack. When adventuring during this holiday season, be very mindful of these changes and choose your ski lines conservatively.

Check AB511 for live updates on road closures.

Confidence

Moderate

Avalanche Summary

Minimal field observations on Monday due to Icefields Parkway closure. Snowballing observed at low elevation avalanche paths along Maligne road.

Few natural small loose dry avalanches have been observed below tree line along the Icefields Parkway corridor on Sunday.Marmot Basin reported several small stiff wind slab avalanches with good propagation on Sunday.

Snowpack Summary

Snowline was at approximately 1800m on Monday. Snowpack below 1800m had moist snow in the top 3- 5 cm. Up to 35 cm of snow has accumulated since December 23rd sitting over a faceted upper snowpack. Strong southwesterly winds creating hard wind slabs in the alpine and tree line. The bottom of the snowpack is weak and consisting of basal facets with pockets of depth hoar. Snow height ranges from 50-120cm.

Weather Summary

TuesdayFlurries.Accumulation: 8 cm.Alpine temperature: High -2 °C.Ridge wind southwest: 10-30 km/h.Freezing level: 1800 metres.

WednesdayCloudy with sunny periods and isolated flurries.Precipitation: Trace.Alpine temperature: Low -10 °C, High -4 °C.Ridge wind west: 15-30 km/h.Freezing level: 1500 metres.

Terrain and Travel Advice

Uncertainty is best managed through conservative terrain choices at this time.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Loose avalanches may start small but they can grow and push you into dangerous 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.

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.