Avalanche Forecast

Issued: Dec 30th, 2014 3:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Persistent Slabs and Wind Slabs.

triley, Avalanche Canada

South Columbia.

Avalanche danger is expected to remain at Considerable during the forecast cold and clear weather for the end of the year.

Summary

Confidence

Fair

Weather Forecast

Clear and cold overnight with alpine temperatures dropping to about -25 and moderate Northeast winds. Winds becoming moderate Northwest during the day on Tuesday and alpine temperatures rising up to about -14 under clear skies. Cold and clear with light Westerly winds on Wednesday. Increasing cloud on Thursday with a chance of light snow in the afternoon.

Avalanche Summary

Skiers triggered avalanches up to size 2.0 and remotely triggered avalanches up to size 1.5 that released 30-60 cm down on the mid-December crust/surface hoar weak layer. Explosives control released avalanches up to size 1.5 on the same persistent weak layer. The persistent slab problem is expected to continue for the forecast period.

Snowpack Summary

There is 10-20 cm of light dry snow that has been transported by Northerly winds into pockets of windsalb in the alpine and at treeline. Below the new snow is the recent storm slab that is 40-90 cm thick and is sitting on a persistent weak layer of crust and surface hoar. The crust extends up to about 2100 metres and seems to be the most reactive at treeline or in the upper below treeline elevations where the surface hoar was well preserved. Fractures have been propagating long distances on this layer and have allowed for remote triggering from adjacent terrain. Deeper in the snowpack there is a hard rain crust from November that may have a weak layer of facets at the interface. This November crust has not been reactive, but continues to be a concern for triggering in shallow snowpack areas.

Problems

Persistent Slabs

The mid-December crust and surface hoar layer is now buried between 50-80 cm and continues to be a concern for triggering by light additional loads like a skier/rider.

Stick to simple terrain, small features with limited consequence and be aware of what is above you at all times.>Use conservative route selection, dig down and test weak layers before committing to anything.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Wind Slabs

Northerly winds continue to transport the recent snow into pockets of windslab in the alpine and at treeline. Watch for areas of reverse loading due to the change in wind direction since the last storm that came out of the Southwest.

Avoid fresh windslabs and areas that have been reverse loaded by changing wind direction.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Dec 31st, 2014 2:00PM