Archived

Avalanche Forecast

Dec 31st, 2014–Jan 1st, 2015

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

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

Regions: Cariboos.

Avalanche danger is expected to rise as new snow adds stress to a touchy and weak snowpack structure.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Snow is expected to begin on Thursday and become more intense overnight and into Friday (up to 30cm by Friday afternoon). Winds are forecast to become moderate to strong from the SW to NW. Freezing level at valley bottom. Snowfall becomes light on Saturday.

Avalanche Summary

Natural avalanches have been reported up to size 2 where the recent storm snow has been transported into a wind slab. Some of these avalanches have released on or stepped down to the mid-December persistent weak layer of surface hoar and crust. Human triggering continues to be likely to very likely due to the storm slab sitting on a hard sliding surface with a weak layer of surface hoar at the interface.

Snowpack Summary

Snow and wind forecast for Thursday and Friday will add stress to an already volatile snowpack. Storm slabs are expected to hide extensive recent wind slabs which formed at all elevations in response to strong northerly winds. Storm slabs or wind slabs may be easy to trigger, and may step down to the persistent weak layer of mid-December surface hoar. The touchy mid-December surface hoar layer is buried under a consolidated slab, up to a metre down. Below 2100 m this slab sits on a thick, solid crust/ surface hoar combination and has been acting as a perfect sliding layer. A hard rain crust with facets from early November is buried more than a metre down and is currently unreactive. However, triggering from shallow rocky and unsupported terrain remains a concern.

Avalanche Problems

Persistent Slabs

A buried surface hoar/ crust layer demands respect. It has been easy to trigger, even from a distance. As new snow builds above this weakness, avalanches are expected to become larger and easier to trigger.

Avoid steep rollovers at and just below treeline where the surface hoar may be well preserved and sitting on a hard crust.>Stick to small features with limited consequence and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 2 - 5

Storm Slabs

New snow and wind are likely to build storm slabs overtop of existing wind slabs.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.>Stick to non-avalanche terrain or small features with limited consequence.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3