Avalanche Forecast

Archived

Jan 13th, 2015–Jan 14th, 2015

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis.

Seek sheltered areas at treeline and below for the best turns. PW

Confidence

Good

Weather Forecast

Temperatures are on the rise, but should remain below freezing in the alpine. It will be mainly cloudy, but when the sun comes out if will have an adverse effect on snow stability, especially on steeper angled aspects facing the sun directly. Keep an eye out for sluffing of snow off of radiation sponges such as cliff faces and rocks due to the sun's warming, which will often create point release avalanches. Ridgetop winds will be in the 35km/hr range from the west.

Avalanche Summary

No new avalanches observed.

Snowpack Summary

Surface hoar growth occurred last night up to 8mm in size. With some clear relatively calm nights ahead will see this growth continue, although this won't be a concern until it is buried. In the alpine and open areas at treeline there are variably distributed windslabs making for tricky skiing. A sun crust formed on solar aspects from last Wednesday's intense sunny period. Sheltered areas are the key to good turns at the moment. Forecasters were in the Hero's Knob area where the Dec. 13th layer was prevalent at treeline and in the sub-alpine elevations. Weak facetted snow crystals were found both above and below this layer giving forecasters concern for human triggering. The basal weak layers are still a concern so much so that it turned forecasters around today.

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.

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.