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Archived

Avalanche Forecast

Feb 7th, 2015–Feb 8th, 2015
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
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
3: Considerable
The avalanche danger rating below treeline will be considerable
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

Regions: Kootenay Boundary.

The storm may have tapered-off, but the snowpack will need time to adjust to the heavy load of the new snow, and water saturation at lower elevations. Conservative terrain selection remains critical.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

The pineapple express will persist for Sunday and Monday, but it will lose much of its "punch". A warm, dry ridge will build for Tuesday.  Sunday: Light precipitation / Moderate southwest winds / Freezing level at 1800m  Monday: 10-15cm of snow at higher elevations / Moderate to strong southwest winds / Freezing levels at 1800m  Monday: A mix of sun and cloud / Light northwest winds / Freezing level at 1800m

Avalanche Summary

Over the last few days there was a widespread natural avalanche cycle to size 3. Most of the avalanches were storm slabs which formed in response to new snow and wind. At lower elevations, a couple of wet slabs to size 3 were observed. With forecast weather storm slab avalanches will remain a concern with the potential to step down to deeper persistent layers. Loose wet and wet slab avalanches will also remain likely.

Snowpack Summary

Heavy precipitation over the past few days has resulted in deep and dense storm slabs above about 1800m. At lower elevations heavy rain has saturated the snowpack. Moderate to strong southwest winds have shifted the new snow accumulations into much deeper deposits in exposed lee terrain. Weaknesses are expected to exist within the new storm snow as well as on a hard melt freeze crust which exists up to 80cm below the surface. This crust, which formed at the end of January, is reported to have weak overlying surface hoar and should be treated with caution.Deeper in the snowpack the mid-January surface hoar remains a concern. It can be found down 60-120 cm across the region, but in most places it is about one metre down. In some locations it has reportedly gained quite a bit of strength, but elsewhere it is still producing "sudden" failures in snowpack tests. The mid-December surface hoar layer is now 80 to 140cm below the surface and has become unlikely to fail. The current storm pattern should be a good test to see if it will become active again.

Avalanche Problems

Storm Slabs

Strong winds, continued snowfall, and high freezing levels are expected to result in natural avalanche activity within the storm snow, or releasing on the late January buried crust.
Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>Good day to make conservative terrain choices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 5

Persistent Slabs

Buried persistent weak layers may be over-loaded by the new storm snow. Any avalanche on these deeper layers would be large and destructive.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar or crust/facet layer.>Choose well supported terrain without convexities.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 3 - 5

Wet Slabs

Continued rain at lower elevations may result in wet slab avalanches running to valley bottoms. Be aware of avalanche terrain that is above you when traveling on lower elevation access trails and roads.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4