Avalanche Forecast

Issued: Dec 27th, 2012 9:18AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Friday: Northwesterly flow tapering off overnight as an upper ridge moves into the region by Friday morning. Light snowfall amounts accompanied by moderate West winds. Treeline temperatures near -7 and freezing levels at valley bottom.Saturday/Sunday: Cloudy skies and light snow fall amounts ending later Saturday night. Ridgetop winds light-moderate from the West. Treeline temperatures near -6. On Sunday the upper ridge gives dry, cooler conditions.

Avalanche Summary

On December 24th Record Mt. had a natural size 2 slab avalanche. Reports indicate that the failure plane was the late November surface hoar layer buried down 115 cm. The avalanche occurred on a East aspect around 1900 m. Reports from the Rossland area suggest that the buried surface hoar is well preserved and the crystals are 10 mm in size. I suggest keeping this on your radar, it may be more suspectable to rider triggers then in the Northern parts of the Region.No new avalanche observations reported on Thursday.

Snowpack Summary

Last week's storm snow seems to be settling with moderate to hard resistant shears in the top meter of the snowpack. Wind slabs have formed and may be easy to trigger, especially on leeward slopes, and behind terrain features (spines, gullies). In sheltered places the slab is still relatively unconsolidated and soft and may not propagate far. Through the region, people continue to monitor the late November buried surface hoar found down around 115-130 cm. Snowpack testing has shown compression and deep tap test results in the hard to very hard range with a variety of fracture characteristics, including no results, breaks and some with sudden results. This layer may be difficult to trigger, but you can expect a consequential avalanche to occur if this layer fails. Dig down, find and test weak layers that may exist in your neck of the woods. The mid-pack is generally well settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Blowing winds from variable directions has redistributed recent storm snow on most aspects. Use extra caution on lee slopes, behind spines, and in wind exposed areas. Reverse loading may catch you by surprise on unsuspecting slopes.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Dig down to find and test weak layers before committing to a line.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Dec 28th, 2012 2:00PM