Archived

Avalanche Forecast

Jan 21st, 2016–Jan 24th, 2016

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

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

2: Moderate

The avalanche danger rating below treeline will be moderate

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: Waterton Lakes.

Friday is not the day to be pushing your limits. Stick to easily managed terrain. Conditions will improve by late in the weekend, but start small and build up, evaluating conditions critically as you go.

Weather Forecast

Strong-Extreme SW winds until Friday evening. A classic chinook...expect the highest windspeeds and freezing levels in the East of the Park. Temperatures may reach 5 degrees in town, and an Above Freezing Layer makes an appearance at treeline early Friday. 5-15cm of new snowfall by Friday evening. The weekend: cooler temperatures and light winds.

Snowpack Summary

Fresh wind slabs are building lee to Moderate - Strong SW winds, sitting atop harder, thicker wind slabs from strong SW winds several days ago. Down 40-50cm is a weak layer: Sun crust on solar aspects, and surface hoar on most non-solar slopes. This layer is producing mainly Moderate-Hard shears. Tests indicate limited propagation potential.

Avalanche Summary

Poor visibility is hampering avalanche observations. Cornices have grown, but proved stubborn to triggering when cut by forecasting staff at treeline elevation ridges. Cornice chunks and ski cutting produced only thin surface Wind Slab results in immediate lees and unsupported features, however areas of thicker buried Wind Slab were avoided.

Confidence

Due to the number of field observations

Avalanche Problems

Wind Slabs

These Wind Slabs are widespread in exposed areas, and may also be found in isolated locations below treeline. Avoid obviously loaded slopes.

Avoid steep lee and cross-loaded featuresIf triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

A weak layer that was buried in early January seems to be gaining strength, but this strength is being put to the test by wind loading, new snow and near-zero temperatures.

Choose conservative lines and watch for clues of instability.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2