Avalanche Forecast

Issued: Dec 1st, 2013 8:30AM

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

jlammers, Avalanche Canada

South Columbia.

Recent snowfall amounts have been highly variable throughout the region. In some areas (particularly the Monashees where accumulations were reported to be the highest), Treeline and Below Treeline danger ratings may be higher than posted.

Summary

Confidence

Good

Weather Forecast

Monday: A mix of sun and cloud with the possibility of light flurries / Light northeast winds / Alpine temperature of -10.0Tuesday: Clear skies / Light north winds / Ridgetop temperature of -18.0Wednesday: Clear skies / Light winds / Ridgetop temperature of -18.0

Avalanche Summary

No reports of recent avalanche activity have been received. This likely speaks more to the lack of observations rather than actual conditions.

Snowpack Summary

Recent storm accumulations have been highly variable throughout the region with roughly 30cm falling in the Selkirks and close to double that in some parts of the Monashees. This new storm slab will increase in reactivity and destructive potential as it deepens or in areas where it has been redistributed and compressed by wind. The new snow covers a variety of old surfaces which include: old wind slabs at higher elevations, melt-freeze crusts on previously sun-exposed slopes and touchy surface hoar in sheltered terrain.In the mid snowpack you may find a layer of surface hoar buried in mid-November ranging from 90cm-130cm in depth. An October crust/facet combo exists near the base of the snowpack. The most likely place you'd trigger this layer is on smooth, planar, high north facing slopes, especially if the snowpack is unusually shallow in that area.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 the new snow.

Problems

Storm Slabs

Touchy storm slabs exist with the potential to create large avalanches. Storm slabs may be more reactive on slopes affected by wind, or in areas where they overlie surface hoar. Sluffing may also occur where new snow is unconsolidated.

Be cautious as you transition into wind affected terrain.>Be cautious of sluffing in steep terrain.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Persistent Slabs

Loading from the recent storm may reactivate persistent weaknesses buried in the mid and lower snowpack. If triggered, avalanches on these layers would be large and destructive.

Caution around large unsupported slopes and areas with a thin or variable snowpack. Persistent slabs have the potential for wide propagation.>Be aware of the potential for large, deep avalanches due to the presence of buried persistent weaknesses.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Dec 2nd, 2013 2:00PM