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Avalanche Forecast

Archived

Dec 20th, 2022–Dec 22nd, 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, Highwood Pass, North 40, Spray - KLakes.

The Avalanche Hazard is Moderate, yet the CONSEQUNCES are high with the Deep Persistent Avalanche Problem. In a Holiday nutshell, the snowpack is weak and untrustworthy. And it is really COLD out there.

Confidence

Moderate

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

In the last few days, we gotten 5-10cm of low density snow that is sitting on top of the recent crop of surface hoar. The current snow pack continues to facet out quickly with the cold weather. Like the rest of the region, there isn't a lot of snow. We have 85cm at tree line and the odd pocket of 1m. What really caught our attention was the snowpack variability based on elevation. The surface hoar from last month is very prominent up to about 2100m. This layer will vary from area to area, but be sure to have a look for it as it is notable. The other general statement is how weak and poor the regional snowpack is. There is a theme of a somewhat settled upper snowpack resting on a foundation of facets and growing depth hoar. Where the snowpack failures occur seems to vary in depth, but the failures are very, very consistent in their character. They are failing fast, with little warning. It's easy to get caught up in the semantics of layer types and descriptions, but at the end of the day we have a nasty weak layer that is predictably failing. Do your homework, dig your holes and be sure you have a good grip on your local terrain before you commit to consequential terrain.

Weather Summary

Wednesday

The cold is hanging on. Expect a mix of sun and cloud with a morning temperature of -36c. No worries, the high is expected to be a balmy -30c with light NE winds.

Thursday

Another day of sun and cloud with a daytime high of -25c and light West winds.

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 aware of the potential for surprisingly large avalanches due to deeply buried weak layers.

Problems

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.