Avalanche Forecast

Archived

Jan 13th, 2023–Jan 15th, 2023

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.

Temperatures will begin to drop overnight and Saturday and a few cms is suspected to fall. The problems associated with the weak base will continue to persist for some time yet to come this season.

Confidence

Moderate

Avalanche Summary

Nothing new observed today.

Snowpack Summary

Overnight and through Saturday we should see a gradual cooling as the cooler air moves back in. The gradual cooling will be coupled with light snowfalls of up to 6cm. What we can expect is a new surface crust below 2000m in many areas. The freezing level climbed to 2200m on friday with +4 at valley bottoms. These warmer temps will help settle out the snowpack a bit but we would need a few continued days of this in order to really improve the conditions.

With regard to the current structure of the snowpack not much is changing. The weak basal facets are still there and can be triggered from thinner snowpack areas and due to the snowpack above having become more cohesive over the past weeks the potential for a large deep full depth avalanche is real. Also in the snowpack the Dec 17th SH layer is down 30-50cm and producing moderate to hard sheers. Regardless of a sheer in the midpack, there is a high likelihood that any avalache will step down and involve the entire snowpack.

Weather Summary

Trace snow accumulation across the Region, though a few west-facing slopes could receive a couple centimeters under the heaviest flurries. Southwest winds will weaken in the morning from 30 to 40 km/h to 15 to 20 km/h around Kananaskis Country (KC). Alpine temperatures -2°C to -6°C across most of the Range, except 0°C to +2°C south of Highwood Pass

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.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.

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.