Avalanche Forecast

Archived

Jan 14th, 2023–Jan 16th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

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.

Pay close attention to temperatures on Sunday. If the cooling trend that is forecast doesn't arrive, we can expect the conditions to remain at considerable.

Confidence

Moderate

Avalanche Summary

One sz 2 slab was observed on the SE aspect of heros know at 2100m. The warm temps was the suspected trigger.

Snowpack Summary

The freezing level on Saturday was around 2100m with moist surface snow below this elevation. In the valley floor, the top 20cm of snow was moist by 1300. So its fair to say over the next few days with the temps dropping we will have a crust forming up to 2100m. Above 2100m the snowpack isnt changing too much. Two main layers are our concern, the December 17th and the basal facets. In field tests on Saturday moderate results were still occurring on both layers. The main concern was the sudden collapse nature of the deep facets. While the midpack is gaining strength, the deeper weak layers of facets and depth hoar is still triggerrable. This is especially true from thinner snowpack areas. Any avalanche triggerred is likely to involve the entire snowpack.

Weather Summary

Temperatures will begin cooling overnight with freezing levels dropping back down towards the valley floor. Winds will remain light but unfortunately precip will also remain light. We are not seeing any significant accumulations in snowfall over the next 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 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.