Avalanche Forecast

Archived

Jan 28th, 2023–Jan 29th, 2023

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.

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 cold arctic air is here! Expect cold temperatures around -25C with light winds. The newly buried melt freeze crust down 10cm is making skiing challenging up to 2200m.

Confidence

Moderate

Avalanche Summary

A few loose dry avalanches at treeline and below up to size 2. No new slab avalanche activity was observed.

Snowpack Summary

On average 10cm of new snow fell at treeline with some areas seeing more and some a bit less. Valley bottoms (where snow is needed the most) was where it was less with only around 5cm accumulation. This new snow is overlying a thin melt freeze crust up to 2100m that makes the skiing very challenging but so far the bond appears to be good. The upper snowpack continues to strengthen with the only notable sheer at the interface with the deeper weak facets in the moderate range. Isolated windslabs were observed in alpine areas on southern aspects from the recent northerly winds but they do not extend far downslope.

As the snowpack above the weaker base becomes more cohesive the potential for wide propagation increases. This will be a common theme this winter and you should always be thinking about consequences of an avalanche.

Turns are pretty hard to come by as one forecaster described the area as the worst they have ever seen.....

Weather Summary

The cold arctic air is here! A high pressure ridge is over us right now that will keep the chance for flurries minimal to non-existent. Cold temperatures will continue with winds out of the NW in the moderate range at upper 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.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.