Avalanche Forecast

Issued: Dec 14th, 2014 8:13AM

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

triley, Avalanche Canada

Kootenay Boundary.

Danger ratings trending down due to low freezing levels after the recent rain.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Mostly clear skies with light Southeast winds overnight. Freezing levels dropping down to valley bottoms and overnight alpine temperatures around -8. Clear with light Southeast winds on Monday and alpine temperatures around -5. Cloud developing on Tuesday as the light winds shift to the South or Southwest and alpine temperatures stay around -7. There is a chance of light flurries with little accumulation on Tuesday. On Wednesday expect mostly cloudy with some sunny breaks and light Southeast winds.

Avalanche Summary

No new reports of avalanches from this region

Snowpack Summary

Rain from the past week has saturated the snowpack in most areas, and a hard crust likely exists to about 2100m. The thickness of the crust will depend on elevation and how much rain fell. The Kootenay Pass is reporting a 9 cm knife hard crust with 5 cm of new snow above, and closer to Nelson up to 2000 metres elevation we have reports of a 7 cm knife hard crust with 1 cm of new snow above. At higher elevations, snow and strong winds have added depth and cohesion to a storm slab which may be sitting on a weak layer of hard rain crust, facets, and/or surface hoar. Near the base of the snowpack is a crust/facet combination which formed in November. This interface remains a concern at higher elevations in many parts of the region as it continues to produce whumpfing, and has the potential for wide propagations.

Problems

Wind Slabs

Pockets of windslab in the alpine developed during the last storm in areas that were above the rain line. These windslabs should be gradually increasing their bond to the old surface below.

Be cautious as you transition into wind affected terrain.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Persistent Slabs

High alpine terrain that did not get rain during the last storm may continue to have a storm slab above a deeply buried crust that could act as a smooth sliding layer.

Avoid large alpine features with smooth ground cover.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 15th, 2014 2:00PM