Archived

Avalanche Forecast

Dec 1st, 2017–Dec 2nd, 2017

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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: South Rockies.

Reactive wind slabs may exist at upper elevations and could step down to deeper weak layers possibly producing a large avalanche. Use a conservative approach and terrain selection as the snowpack remains variable in the region.

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Saturday: Mostly cloudy with isolated flurries and ridgetop winds moderate from the West. Alpine temperatures near -10. Freezing levels 1100 m. Sunday: Mix of sun and cloud. Ridgetop winds light from the North West. Alpine temperatures -12 and freezing levels near 800 m. Monday: Mostly sunny with ridgetop winds light from the South West. Alpine temperatures near -10 and freezing levels at valley bottom.

Avalanche Summary

No new avalanche observations have been reported from the region. There is potential for triggering reactive wind slabs on leeward slopes. Smaller avalanches may step down and trigger larger avalanches on buried weak layers deeper in the snowpack. Please submit your observations this weekend to the Mountain Information Network.

Snowpack Summary

The snowpack remains highly variable with very little information regarding snowpack structure within the region. Average snowpack depths at upper elevations range from 60-110 cm with scoured snow surfaces on southwesterly slopes and deeper pockets of wind slab on northeasterly slopes. Below the surface exists a series of crusts that were buried near the end of November approximately 40 cm and 70 cm down. Deeper in the snowpack a third crust from the end of October exists as a "facet/crust" combo and has been identified as a potential sliding interface where snowpack testing North of the region (Kananaskis Country) is proving hard but sudden collapse results.

Avalanche Problems

Wind Slabs

Stiff wind slabs could be reactive to rider triggers at treeline and in the alpine on leeward and cross-loaded slopes.

Use ridges or ribs to avoid pockets of wind loaded snow.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2

Persistent Slabs

There are several crusts now buried within the snowpack. Use extra caution in thin snowpack areas where it may be possible to trigger a deeper layer. Triggering a wind slab may also have the potential to step-down to a deeper layer.

Be aware of thin areas that may propogate to deeper instabilites.If triggered wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3