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Avalanche Forecast

Jan 14th, 2021–Jan 17th, 2021
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Waterton Lakes.

Wednesday's storm has formed widespread wind slabs at upper elevations, and a breakable crust below treeline. Choose moderately angled terrain with low consequence, avoid walking under cornices, and travel downhill through the burnt forest with care.

Weather Forecast

Friday: Cloudy with sunny periods and an alpine inversion. Strong to Extreme W winds, alpine high 0 early in the morning dropping to -5 in the afternoon

Saturday: Mainly cloudy with isolated flurries. Moderate NW winds, inversion with alpine high of -5

Sunday: Cloudy with flurries. Inversion breaking down during the day, with strong to extreme W wind

Snowpack Summary

The storm brought 30cm of new snow. Upper elevations are heavily wind affected, and new windslabs will be found in lee areas. Below 1900m rain during the storm formed a breakable crust which can be found under 5cm of fluff. The Dec 9th crust can be found down 70-100cm at Cameron Lake. Areas east of the divide hold a thin & faceted snowpack.

Avalanche Summary

Good visibility on Thursday showed a widespread avalanche cycle in most wind loaded features from Size 1 to Size 3 that occurred on Tuesday night/Wednesday morning. A couple of these involved step down avalanches to deeper weak layers, including a size three with impressive propagation in  a thin convexity in Rowe Bowl.

Confidence

The weather pattern is stable

Avalanche Problems

Wind Slabs

New snow combined with strong winds has formed slabs which will take time to heal. Choose conservative terrain.

  • Choose low angle and supported terrain. Avoid large features.
  • Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2

Persistent Slabs

Isolated persistent slab avalanches were observed after the last storm. This a reminder that they can still be triggered by cornice fall or smaller avalanches stepping down in thin snowpack areas.

  • Pay attention to overhead hazards like cornices which could trigger the persistent slab.
  • If triggered the wind slabs may step down to deeper layers resulting in larger avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 3