Avalanche Forecast

Archived

Feb 2nd, 2015–Feb 3rd, 2015

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis.

The snow has taken a turn for the better. Sheltered areas at treeline are the place to find decent snow right now. Watch for new slabs as you approach treeline.

Confidence

Good

Weather Forecast

Mainly cloudy with isolated flurries tomorrow. High of -7 at 2500m. Winds gusting to 50km/hr from the west.

Avalanche Summary

Nothing from the last 24hrs, but there is a fair bit of older action from open areas at treeline and immediate lee areas at lower the alpine elevations. Sz2's were spotted mostly on the south & south east aspects. The eastern side of the road also had some recent activity in the alpine. Most involved the basal layers.

Snowpack Summary

We are dealing with a complex snowpack right now. Below treeline has 16cm's of new snow sitting on top the January 31 crust. In some places we've found surface hoar on top of the crust, and in others a thin layer facets. So far the distribution of the surface hoar is unknown. Beneath the crust, the January 16th surface hoar is also present in unpredictable places. Luckily, there does not appear to be an avalanche problem with any of these layers. At treeline, the snowpack starts to have a series of windslabs that are reactive to stability tests. In today's profile (top of the Dog leg run), immediatley below the Jan 31st crust there is a thin, hard windslab that is reacting in the moderate range (CT11, SC down 20cm's). This suggests there are human triggerable windslabs out there in the right piece if terrain. At upper treeline and alpine, the winds continued to transport snow. A reverse loading pattern was noted today. The new slabs are sitting on a hardslab that likely has a poor bond. These slabs are easily spotted and avoidable.

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.