Date issued

Jan 21, 2018 - 4:16 PM

Valid until

Jan 22, 2018 - 4:00 PM

Prepared by

conrad janzen

Enjoy the new snow, but remember that there is enough whumphing and avalanche activity on the mid-pack weak layers to continue with a cautious approach to larger more committing terrain.

Regular season
Sunday - January 21, 2018
Alpine

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Treeline

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Below Treeline

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

Monday - January 22, 2018
Alpine

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Treeline

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Below Treeline

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

Tuesday - January 23, 2018
Alpine

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Treeline

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Below Treeline

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

Avalanche Problem 1: Wind Slabs

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

Recent winds and snow have formed wind slabs in immediate lee areas and caused sluffing in steep rocky terrain. Pay attention to the surface texture and local wind transport patterns as these will be the biggest indicator of the wind slab problem.

Travel and Terrain Advice
  • Use caution in lee areas. Recent wind loading have created wind slabs.
  • If triggered the wind slabs may step down to deeper facet layers resulting in larger avalanches.

Avalanche Problem 2: Persistent Slabs

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

The Dec 15 surface hoar/facet layer continues to cause concern with forecasters. Only a few avalanche observations have been reported on this layer recently, but widespread cracking and whumphing is still occurring when traveling in the back country.

Travel and Terrain Advice
  • Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Use conservative route selection, choose supported terrain with low consequence.

Avalanche Summary

Two size 2 slabs triggered by wind loading and cornice failures were observed in the last 24 hours on Quartz Ridge and the 93 North. These both appeared to fail on a mid pack layer of facets. One skier triggered size 1 wind slab was reported in Semi Circular Bowl near Lake Louise. Numerous large sluffs out of steep rocky terrain in the last 36 hrs.

Snowpack Summary

Newly formed wind slabs in immediate lee features at alpine and treeline elevations. In sheltered areas the upper snowpack consists of 20-30cm of soft slab over the Jan 6 surface hoar. The Dec 15 layer of surface hoar and facets is down 40-60 cm and is reactive in snow tests. Below treeline much of the snowpack is facetted with little structure.

Weather Forecast

We should see some new snow Sunday night and into Monday with models showing between 5-10 cm of snow at treeline. Temperatures will remain below freezing with -10 to -12'C at upper elevations. 3000m winds will be moderate/strong SW Sunday night then dropping Monday. Tuesday sees a slight clearing trend and perhaps some more flurries on Wednesday.

Danger Ratings Explained

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

3 - Considerable

Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

Natural avalanches possible; human-triggered avalanches likely.

Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.

4 - High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human-triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

5 - Extreme

Avoid all avalanche terrain.

Natural and human-triggered avalanches certain.

Large to very large avalanches in many areas.

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