Avalanche Forecast

Issued: Nov 29th, 2013 8:33AM

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

jlammers, Avalanche Canada

South Columbia.

Saturday`s danger ratings are based on light snowfall overnight Friday and Saturday. If new snowfall amounts are upwards of 15cm in your area, actual danger ratings may be higher.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain on Sunday

Weather Forecast

Saturday: Mostly light snowfall with moderate westerly ridgetop winds. Freezing level around 1400 m.Sunday: Heavy snowfall with strong westerly winds. Freezing level around 1400m.Monday: Light to moderate snowfall with light southwest winds. Freezing level dropping to 1000m

Avalanche Summary

No reports of recent avalanche activity have been received. I would expect a new round of storm slab activity with weather forecast for the weekend.

Snowpack Summary

Total snowpack depths range from 110 to 160cm at treeline across the region. On the surface a newly developing storm slab covers a variety of old surfaces which include: old wind slabs at higher elevations, melt-freeze crusts on previously sun-exposed slopes and surface hoar in shaded terrain.In the mid snowpack you may find a layer of surface hoar buried in mid-November ranging from 50-90cms in depth. An October crust/facet combo exists near the base of the snowpack. These persistent layers are slowly becoming more difficult to trigger. However, they have the potential to cause large and destructive avalanches, and may 'wake-up' with the increased load of new snow forecast for the next few days.

Problems

Persistent Slabs

Persistent slab avalanches have become less likely; however, if triggered they may be large and destructive. Persistent slabs may also `wake-up` with new snow forecast for the weekend.

Dig down to find and test weak layers before committing to a line.>Caution around large unsupported slopes and areas with a thin or variable snowpack. Persistent slabs have the potential for wide propagation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Storm Slabs

New snow will add to a developing storm slab problem. New storm slabs may be extra touchy in wind-affected terrain, or in areas where recently buried surface hoar exists.

Be cautious as you transition into wind affected terrain.>The new snow may require several days to settle and stabilize due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 30th, 2013 2:00PM