Avalanche Forecast

Archived

Dec 7th, 2022–Dec 8th, 2022

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, Bow Valley, North 40, Spray - KLakes.

Winds will increase tomorrow so watch for windslabs to get more reactive in alpine terrain along ridgelines. This week we have also seen small avalanches running far and fast on the weak basal layers entraining all the weak snow so think about this concern in steeper terrain.

Confidence

Moderate

Avalanche Summary

After a flight across the region on Wednesday a few small slab avalanches were observed in gully features in the alpine and evidence of skier triggered avalanches at treeline were also observed that ran far in the basal facets.

Snowpack Summary

A few slab avalanches (both human and naturally triggered) in steeper terrain have been noted in recent days. As the winds increase on Thursday, we expect windslabs to become more widespread on lee aspects (N and E).

The basal layers of the snowpack are typical of the eastern Rockies for this time of year, and consist almost entirely of facets. Unfortunately this condition is not going anywhere fast, and may be with us for the season. Any avalanche that initiates in the upper snowpack is likely to fail in the deeper weak facets and involve the intire snowpack.

Weather Summary

As temperatures warm up the winds are forecast to arrive with a bit more vigour on Thursday. 40-60km/hr winds out of the SW are forecast with temperatures in the -10C range. Unfortunately after a good talk with our colleagues at Meterogical services of Canada on Wednesdaym there doesnt look to be to much in the way of new snow forecast for this week.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

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

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.