Avalanche Forecast

Archived

Jan 11th, 2023–Jan 12th, 2023

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, human triggered possible.

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.

Although the hazard has decreased slightly, forecasters are still very concerned with the snowpack structure. The bottom half of the snowpack is very weak, and full-depth avalanches will remain a real concern for some time to come. Very conservative route selection is still in order.

Confidence

High

Avalanche Summary

Nothing new observed today.

Snowpack Summary

The snowpack has seen very little change in recent times. The mid-December surface hoar layer down 30cm at Treeline continues to react as a persistent slab with compression tests in the moderate range. Below this, the remainder of the snowpack is heavily facetted. Any avalanche triggered in the upper snowpack will almost certainly step down to the ground.

Despite a slight improvement in the hazard, forecasters are approaching all terrain conservatively and do not have much confidence in the snow pack, as it's one of the worst we've seen in many, many years.

Weather Summary

Thursday will be very windy with a mix of sun and cloud. Ridgetop temperatures should reach -5C as a high. A trace amount of flurries are possible for Friday with rain at lower elevations.

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.