Avalanche Forecast

Archived

Feb 28th, 2017–Mar 1st, 2017

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

Kananaskis.

The overnight and early morning winds will strongly influence the hazard tomorrow. Expect windslabs at treeline and above if there is widespread snow transport. Alpine hazard could jump to considerable.

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

Up to 5cm tonight. Tomorrow will be mainly cloudy with isolated flurries. The alpine high will be -15 with wind s picking up to 45-50km/.hr from the west at treeline. The alpine will much stronger winds. One forecast had then at 100km/hr in the morning.

Avalanche Summary

Nothing new was seen today.

Snowpack Summary

A flight around the area today gave us a good look at the snow conditions. In general we are still seeing a low elevation snowpack that is well settled up top, but weak deeper down. There are two apparent crusts in the top layers, but neither of which pose a problem yet. This deep weakness is a widespread problem. Treeline and alpine elevations has had a few cm's of snow with not a lot of wind effect. Some transport was noted, but most of it was localized and of little consequence. At these upper elevations, the problem layers are down almost a meter. Some near surface slabs exist as do buried sun crusts on solar aspects. Unlike the low elevation, these crusts may be a concern in steep 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.

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.