Avalanche Forecast

Archived

Dec 9th, 2022–Dec 10th, 2022

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 unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Forecasters were able to easily remote and skier trigger avalanches failing down 40-50cm at treeline on Friday. Avoid steep, convex and unsupported slopes as the snowpack adjust to this new load.

Confidence

High

Avalanche Summary

Numerous skier controlled sz 1 avalanches at treeline triggered by forecasters down 40-50cm. No new slab avalanche activity in areas travelled Friday in alpine areas.

Snowpack Summary

10-15cm of snow fell closer to the divide overnight bringing our recent snowfall totals up to 30cm (ish). This snow was being moved around in the alpine by moderate Sw winds building new windslabs along ridgelines. Forecasters were getting cracking and whumpfing as they travelled. At treeline all the new snow is sitting on the weak facetted base. As it has seen some winds and settlement over the past few days it has formed a more cohesive upper snowpack layer that is failing down 40-50cm at the interface with the basal facets. This interface is proving to be touchy and failing in any steep piece of terrain. As we travelled around features on Friday we were able to remote trigger slopes from 10-20m away easily. The snowpack was constantly talking to us with settlements and cracking. A Profile at treeline has moderate compression test scores down 50cm but very sudden in nature. A good time to use conservative terrain.

Weather Summary

Winds will continue to be in the 40-60km/hr range out of the SW on Saturday with light flurries forecast along the divide. Temperatures will be in the -10c range during the day so not to darn cold!!!

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be especially cautious as you transition into wind affected terrain.
Avoid convexities, steep unsupported terrain and rocky outcroppings.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

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.