Archived

Avalanche Forecast

Feb 5th, 2018–Feb 6th, 2018

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

Regions: Kananaskis.

Avoid avalanche terrain. A large-scale avalanche cycle is on-going.

Confidence

High -

Weather Forecast

Tuesday will be mainly cloudy with isolated flurries. Ridge-top winds will be from the west at 25 km/h and a high of -13 C. Another storm will bring up to 25cm of new snow late Wednesday and into Thursday.

Avalanche Summary

A large-scale natural avalanche cycle occurred in the past 24hrs on all aspects in the Alpine up to size 3.5. A few slabs up to size 2.0 also initiated at Treeline. Smaller loose dry avalanches were widespread across all Treeline and Alpine terrain today. Explosives control work today on EEOR produced size 2.0 avalanches.

Snowpack Summary

Another 15cm of new snow brings recent storm snow totals to between 50 and 60cm. This has fallen with relatively little wind effect in the southern part of the forecast area, but more wind effect is evident up north. In the Alpine fresh wind slabs have formed on all aspects. A large natural avalanche cycle occurred over the last 24hrs associated with these fresh wind slabs. In some cases, avalanches stepped down to deeper weak layers such as the Jan 6 surface hoar and the Dec 15 surface hoar/sun crust/facet layer, producing large to very large avalanches. Forecasters continue to monitor multiple buried weak layers between 50 and 150cm down into the snowpack. In addition, the November crusts layers have recently become active in a few isolated avalanches in shallow snowpack areas.

Avalanche Problems

Wind Slabs

Wind slabs are failing on all aspects in the Alpine and at Treeline producing large to very large avalanches. Be aware of exposure to run-out zones. In many cases these avalanches are stepping down to the deeper buried weak layers.

Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1.5 - 3.5

Persistent Slabs

Several buried weak layers of concern exist down between 50 and 150cm. Loose dry slides or wind slabs initiated in the upper snowpack are often stepping down to these weak layers.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Avoid convex rolls at and below treeline where buried surface hoar may be preserved.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1.5 - 3.5

Loose Dry

Ice climbers, avoid gullies. Expect sluffing in steeper terrain. Some sluffs are triggering slabs on the underlying slopes.

Avoid areas with overhead hazard.Sluffs may trigger deeper instabilities.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 2