Avalanche Forecast

Archived

Mar 7th, 2024–Mar 8th, 2024

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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Beautiful weather for a ski tour or snowshoe loop over the next couple of days. It will remain important to limit overhead exposure and choose very conservative terrain while our snow pack adjusts.

A Special Public Avalanche Warning is in effect and has been extended. Click the red SPAW link for details.

Confidence

High

Avalanche Summary

Natural activity has continued from yesterday to today. Most new avalanches have been in the high alpine, and with impressive propagation. Mt Shark had a large avalanche with a crown well over 1km. Forecasters also witnessed a pair of skiers kick out a sz1.5 windslab today in Tryste Chutes.

Snowpack Summary

No new snow overnight. Fresh windslabs from yesterday and the day before are evident in the alpine and treeline. Natural avalanche activity has tapered, but there's still new avalanches occurring. Most are in steep, rocky alpine terrain. Only minor settlement yesterday, likely due to the fluctuating temperatures and little new snow.

Weather Summary

Friday will be very similar to today. Thin cloud for most of the day, but still more or less blue skies for the day. Temps will start cold at -19, but warm to about -3. Winds will be light with the occasional gust in the afternoon.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Remote triggering is a concern, watch out for adjacent and overhead slopes.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.

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.

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.