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Avalanche Forecast

Feb 1st, 2015–Feb 2nd, 2015
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
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
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: South Columbia.

Avalanche danger will rise as a soft slab forms above a widespread layer of surface hoar and a crust. Danger may be lower than forecast in areas that that receive less snow.

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

A frontal system will bring another 10 to 15cm of new snowfall to the region overnight on Monday with 5 to 10cm expected for Tuesday. A ridge of high pressure building over the province Wednesday will bring dry conditions. Winds will belight to moderate from the west to southwest. Freezing levels will remain at valley bottom until at least Tuesday.

Avalanche Summary

There was a widespread avalanche cycle earlier in the week that produced numerous large to very large avalanches. Natural activity has now eased, but the present of persistent layers in snow pack suggest that it may be possible for humans to trigger an avalanche. Forecast snow above a crust and SH means a reactive soft slab is likely to form.

Snowpack Summary

Up to 25 cm of new snow overlies a variety of old surfaces. A crust formed last week at most elevations. In some places it was breakable in others it was supportive. A thin widespread layer of surface hoar lies above this crust. At the highest elevations the old surface was widely wind-affected. Deeper in the snowpack the mid-January surface hoar remains a concern. It can be found down between 40 and 100 cm. In some locations it has reportedly gained quite a bit of strength, but elsewhere it is still producing sudden (popping) failures in snowpack tests. This spatial variability means we'll have to keep an eye on it for a while yet. The mid-December surface hoar layer is now 80 to 140cm below the surface and has become unlikely to fail.

Avalanche Problems

Storm Slabs

A thin soft slab will form as the snow accumulates.  A layer of recently buried surface hoar above a crust could make for touchy avalanche conditions.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Persistent Slabs

A layer of surface hoar buried in the upper meter of the snowpack remains a concern, especially at treeline and above. A large trigger, like an avalanche in motion could trigger deeper persistent weaknesses.
Choose well supported terrain without convexities.>Be aware of thin areas that may propagate to deeper instabilities.>

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 5