Avalanche Forecast

Archived

Mar 12th, 2025–Mar 13th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

The hazard has dropped to CONSIDERABLE, but many slopes are still primed for human-triggering. Extensive whumpfing and some recent events indicate a strong possibility of remote triggering. Stick to low angle terrain and avoid any overhead hazard. The skiing is good, but this is not the time to jump into steeper terrain.

Confidence

Moderate

Avalanche Summary

One size 3 or 3.5 persistent slab was observed in the Murray Twins area today. This avalanche exhibited wide propagation and ran far. Numerous avalanches were also heard, but not observed due to poor visibility. The natural avalanche cycle is tapering, but some large results are still occurring.

Avalanche control occurred on EEOR today producing 4 size 2 avalanches. Some of these slides showed good propagation across the terrain feature.

Snowpack Summary

Recent storm snow has settled to 30 to 40cm, with the surface becoming moist on solar aspects. This snow overlies a sun crust on solar aspects, and facets or a hard wind slab on polar aspects. Wind slabs are present at higher elevations in lee and cross-loaded features.

In addition, a dense persistent slab sits on the Jan 30th layer down 60 to 90cm. This slab is widespread through the region and covers the very weak mid-pack and basal layers. This combination is producing widespread large settlements with skier traffic, which indicate a collapse of this dense layer onto the weaker base - a perfect recipe for avalanches.

Human triggering of the wind slab and/or the persistent slab is very likely, and several large naturally triggered avalanches are still occurring.

Traveling off of established skin tracks at lower elevations is very challenging due to the weak nature of the snowpack.

Weather Summary

Thursday will be mainly cloudy with light flurries. Accumulations should be between 2-5cm during the day with up to 10 or 15cm by midnight Thursday. Winds will be moderate from the SW with a high temperature of -2C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Remote triggering is a big concern, be aware of the potential for wide propagations and large, destructive avalanches at all elevations.
Choose simple, low-angle terrain without steep convex rolls.
Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.

Problems

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.

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.