Avalanche Forecast

Issued: Dec 23rd, 2012 9:15AM

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

Avalanche Canada ghelgeson, Avalanche Canada

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South Columbia.

Lower danger ratings in the alpine should not be seen as carte blanche for bigger terrain.

Summary

Confidence

Good

Weather Forecast

Monday: Light ridgetop winds out of the E. No Snow. 1500m temp: -15 Freezing level: SurfaceTuesday: Light SE ridge top winds. 1500m temp -13 No snow. Freezing Level: SurfaceWednesday: Light SW ridge top winds. Treeline temp -13. No snow. Freezing Level: Surface

Avalanche Summary

No reports of big natural avalanches in the Alpine yesterday.  There were a number of skier controlled avalanches to size 1.5.  These avalanches were failing as soft slabs in wind exposed terrain. 

Snowpack Summary

An average of 150 cm of storm snow fell in the last 10 days across the region. Winds picked up Wednesday/Thursday of this week forming large wind slabs in the Alpine.  This generated a limited avalanche cycle to size 3 that persisted through Friday.  It sounds like these slabs are settling out but I'm still suspect of them, especially on steep unsupported features. New (relatively) thin wind slabs involving Saturday nights snow may still be an issue Monday. There are some reports of a suncrust down around 100 cm in steep south facing features. The mid-pack is reported to be well settled.  I haven't heard of any test results involving the late November surface hoar in the last five days. The early November crust, near the base of the snowpack has also been inactive as of late. It's important to note that professionals are still cautious about these lingering persistent slab problems, but the likelihood of triggering is low. Be wary of steep complex terrain with a shallow snowpack, where triggering a persistent weakness is more likely.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs 10 -20 cm in depth will likely remain sensitive to human triggering Monday. These thin slabs rest on deeper slabs crated mid week which could still be a problem in steep unsupported alpine terrain. 
Be cautious as you transition into wind affected terrain.>If you venture into the open, start with small, low consequence terrain. You need to carefully evaluate how the upper 75 cm of the snowpack is behaving before committing to more serious lines.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 24th, 2012 2:00PM

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