Avalanche Forecast

Issued: Dec 24th, 2012 9:09AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

The unsettled weather pattern has taken a turn. A weak high pressure system builds in the wake of another approaching Pacific Frontal system and the region is expected to see light amounts of new snow starting midday on Christmas. Happy Holidays!Christmas Day: Snow amounts near 5 cm accompanied by moderate Southerly ridgetop winds. Alpine temperatures near -10, with freezing levels near 600 m in the afternoon.Wednesday: Snow amounts 5-10 cm with ridgetop winds moderate from the SW. Alpine temperatures near -9, and freezing levels near 800 m.Thursday: Scattered cloud and mainly dry. Ridgetop winds light from the West. Alpine temperatures light from the West and freezing levels at valley bottom.

Avalanche Summary

Overnight Saturday natural avalanches occurred during the storm on SE-S aspects up to size 1.5, and mainly from steep, rocky terrain. Explosive avalanche control done on Sunday revealed numerous slab avalanches up to size 2.0 on SE-S aspects. Loose snow avalanches up to size 1.0, and one slab avalanche size 1.5 were easily skier triggered from NW aspects. The previous storm snow is likely touchy to rider triggers, it make take a couple days before it settles out.

Snowpack Summary

Around 110 cm new snow has fallen over the past week. The recent storm snow seems to be settling with moderate to hard resistant shears in the top meter of the snowpack.  In areas of wind effect, expect the storm slab to be stiffer, easy to trigger and more reactive. In sheltered places the slab is still relatively unconsolidated and soft and may not propagate far. In some areas through the region, people continue to monitor the late November buried surface hoar found down around 130 cm. Test results are in the hard to very hard range with sudden results. This layer may be difficult to trigger, but you can expect a consequential avalanche to occur if this layer fails. Deeper in the snowpack sits a well settled mid-pack. 

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs continue to be touchy to rider triggers. Use extra caution on lee slopes, behind spines, and on wind exposed areas. The recent low density snow may also be transported by southwest winds building wind slabs on North through East aspects.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Be cautious as you transition into wind affected terrain.>The best powder will be found in sheltered locations.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 5

Valid until: Dec 25th, 2012 2:00PM

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