Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Carefully assess wind loaded features in the alpine and exposed areas of treeline. If triggered these layers could wake up the deeper layers of the snowpack.
Extreme terrain has been actively been producing small natural avalanches as well. Be mindful of the overhead hazard.
Confidence
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Avalanche Summary
Ski hills are reporting results on the basal facets up to size 3. Additionally, windslabs have been reactive to skier traffic as well as explosives up to size 1.
Within the last 24-48h there have also been numerous natural avalanches out extreme terrain to size 1.5, loose dry as well as windslabs.
Snowpack Summary
10-20 cm of recent snow have formed windslab's in the alpine and exposed areas of treeline. 30-50 cm overlies the Dec. 31 surface hoar/sun crust. Below this, in the mid-pack, two crusts (Dec. 22 and Dec. 5) exist as high as 2350m and have been providing the primary support for skiing. The base of the snowpack remains weak with depth hoar and facets.
Banff Visitor Safety dug a snow profile around Sunshine ski hill for more details.
Weather Summary
Saturday will bring scattered flurries and mod to strong SW winds. Valley bottom temperatures will rise to around -8.
Sunday should be slightly warmer than Saturday, with -6 as the high at valley bottom. 2-5 cm of snow is being forecast as well with strong southerly winds.
For more information, click here for the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avalanche Problems
Wind Slabs
With stronger winds forecast for Friday and lots of snow available for transport, fresh and reactive wind slabs can be expected in the alpine and open areas near treeline.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Loose Dry
Increased SW winds may result in dry loose avalanches out of steep alpine terrain. Avalanches likely will be small, but will be a concern if funneled into a terrain trap or gully.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1.5
Deep Persistent Slabs
The base of the snowpack consists of weak facets and depth hoar. There has not been much recent activity on this layer but forecasters are still warry of this problem. Use caution in steep terrain, large planar slopes, and thin areas where failures on these basal facets are more likely to propagate.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 2.5