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Archived

Avalanche Forecast

Jan 16th, 2015–Jan 17th, 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
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

New snow and wind are forming small touchy slabs above a widespread layer of surface hoar.  Watch for terrain traps that could magnify the consequences of getting surprised by a small slide

Confidence

Good - Forecast snowfall amounts are uncertain

Weather Forecast

Synopsis: The next strong front is forecast to move across the province on Sunday before a ridge of high pressure builds that looks to last for several days. Saturday: Snow starting in the evening with accumulations of up to 20cm around Kootenay Pass, moderate south westerly winds and freezing level at valley bottom. Sunday: Cloudy with flurries and moderate westerly winds. Monday: Mainly cloud with moderate westerly winds.

Avalanche Summary

Several small avalanches were reported to have released in windload features on Friday. Recent avalanche reports have described large avalanches ranging from size 2.5 to 3 releasing on persistent weak layers deep in the snowpack. Several of these avalanche were remotely triggered by ski touring groups from distances as far as 100m.

Snowpack Summary

Friday's snowfall buried a layer of large surface hoar or facets. In many places these week crystals sit above a thin crust which can be found up to about 1900m on north aspects and all the way to ridgeline on south aspects. While this layer is developing our main concern continues to be deeper crust/surface hoar combo buried in mid-December. This weak layer can be found 60-120cm down and still has the potential to be triggered by people. Near the base of the snowpack the facet/crust layer from November has mostly been dormant, however, isolated recent activity in the Bonnington Range suggests that this layer may still be reactive in isolated terrain.

Avalanche Problems

Wind Slabs

The recent snowfall buried a layer of surface hoar above a crust. Moderate winds are redistributing this snow to form touchy windslabs in lee features.
Enter your line well below ridge crests to avoid wind loaded pillows.>Avoid wind loaded features at and below treeline where buried surface hoar may be preserved.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 4

Persistent Slabs

Wind slab avalanches may be able to trigger deeper weak layers, creating surprisingly large avalanche. Persistent slabs may also be triggered by the weight of a person or snowmobile in specific areas such as thin spots or convexities in the slope.
Smaller avalanches may trigger deeper instabilities.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 3 - 6