Avalanche Forecast

Archived

Jan 8th, 2023–Jan 10th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

A bit of new snow may fall overnight Sunday and into Monday, but this will do little to change the current conditions. It is critical to stay disciplined and stick to low angle, low consequence terrain with no overhead hazard. The snowpack is still prime for human triggering due to the persistent weak layers at the bottom of the snowpack.

Confidence

High

Avalanche Summary

One new size 1.5 slab avalanche was observed in the north bowl of Tent Ridge. This naturally triggered avalanche failed in the basal facets and scrubbed to ground.

Snowpack Summary

You may have noticed that very little has changed in our recent snowpack summaries, and that's because nothing is really changing. The snowpack is still very weak and generally scary. The mid-December surface hoar layer down 30cm at Treeline is reacting 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.

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

Sunday night could bring a windy pulse of weather with between 2 and 6cm of snow. By Monday morning the winds should settle down and be light from the SW with temperatures climbing to -6C.

Tuesday will be cloudy with a few more flurries and seasonal temperatures.

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.