Avalanche Forecast
Regions: Bow Valley, Highwood Pass, Kananaskis, 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.
Avalanche Problems
Persistent Slabs
This sits upon weak faceted crystals, sun crust or a dense layer that are perfect for slab avalanches. This layer will not react well to new loading, or even re-loading from wind.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1.5 - 3.5
Wind Slabs
If triggered, these are likely to step down to the persistent slab and then to the basal facets.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Very Likely
Expected Size: 1.5 - 2.5