Avalanche Forecast

Archived

Mar 3rd, 2023–Mar 4th, 2023

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.

Watch for windslabs as you transition into treeline and above terrain. A great nugget of advice was recently passed on from a seasoned avalanche professional; Its a winter for touring not turning. Think about the weak base layers and the potential for a large avalanche.

Confidence

Moderate

Avalanche Summary

One new sz 2 avalanche was observed in the Buller Mountain area that was triggerred by a cornice collapse.

Snowpack Summary

Up to 35cm of recent storm over the past few days is being moved around by the strong winds creating and adding to the previous windslabs that existed in the region. Field teams have been finding easy shears down 25-35cm, and these shears that are reactive to skier traffic. Moderate shears also persist down 30 to 50cm on various versions of old wind slab interfaces. The midpack is strong in deeper snowpack regions near the divide, but the basal facets/depth hoar persist. An avalanche initiated in the upper snowpack could easily step down to the deep persistent weak layers, causing a very large avalanche. Always have full depth avalanche on your mind.

Weather Summary

Well the light snow did continue during the day but now seems to be tapering off here later in the afternoon. Saturday will be light for winds and a mix of sun and cloud but... cooler air is moving in so overnight lows will be around -20C. Daytime highs will get up to -12C but its still winter out there. Not much for new snow in the near future.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

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.