Avalanche Forecast
Regions: Bow Valley, Highwood Pass, Kananaskis, North 40, Spray - KLakes.
Westerly winds and up to 10cm of snow on Thursday is adding more load to the current windslab problem at treeline and above. Be aware of the potential for large avalanches that involve the entire winters snowpack. Thin snowpack areas should be avoided.
Confidence
Moderate
Avalanche Summary
No new avalanches were observed on Thursday but visibility was limited due to snowfall during the day and associated clouds.
Snowpack Summary
Up to 35cm of recent storm over the past few days is being moved around by the strong winds creating and adding to the previous windslabs that existed in the region. Field teams have been finding easy shears down 25-35cm, and these shears that are reactive to skier traffic. Moderate shears also persist down 30 to 50cm on various versions of old wind slab interfaces. The midpack is strong in deeper snowpack regions near the divide, but the basal facets/depth hoar persist. An avalanche initiated in the upper snowpack could easily step down to the deep persistent weak layers, causing a very large avalanche. Always have full depth avalanche on your mind.
Weather Summary
Strong SW winds continued on Thursday but are forecast to become more moderate by friday morning. Another 5cm of snow is likely to fall overnight with temperatures around -15 in the morning warming up to -11 by mid day. Its still full on winter out there these days!
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Avalanche Problems
Wind Slabs
Recent variable strong winds have created and added to previous windslabs that formed in Alpine and treeline areas. In addition, there are several iterations of buried wind slabs formed in previous wind events down 30 to 50cm in the snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
The alpine is still variable in total amounts of snow but the basal layers haven't changed. The entire lower half is either facets, or depth hoar. Thin weak areas should be treated as suspect and avoided.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3.5