Avalanche Forecast

Issued: Dec 24th, 2014 8:29AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Keep it conservative and give the snowpack a few days to sort itself out before thinking of venturing into more complex terrain.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: The Pacific storm cycle has come to a close, a dirty ridge builds in its wake allowing freezing levels to drop back to valley bottom. Look for cooler temps and mid-level cloud through the holiday weekend.Thursday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Light, Variable | Ridgetop: Moderate, WFriday: Freezing Level: Valley Bottom; Precipitation: Nil; Treeline: Light, SW | Ridgetop: Moderate, NWSaturday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Moderate, SW | Ridgetop: Moderate, NW

Avalanche Summary

One size 2 natural avalanche was reported on Sunday. On Monday, no natural avalanche activity was reported, but explosive avalanche control produced avalanches up to size 2.5, initiating in wind slab, then stepping down to the crust. Not much activity to report from Tuesday. If you have any avalanche observations to report, please send an email to forecaster@avalanche.ca.

Snowpack Summary

Prior to Tuesday nights 15 - 20 cm, generally light amounts of snow have fallen in the last few days. In the alpine, winds have been conducive to blowing this snow into wind slabs in exposed lee areas. 30 - 50 cm below the surface (more in wind affected areas) you are likely to find a crust that may have surface hoar on top of it. The crust is reported to extend into the alpine to at least 2100 m; the surface hoar was reported to be most reactive on shady aspects around treeline and just below, between around 1600 m and 1900 m. Where the crust exists, it is effectively bridging triggers from penetrating to deeper persistent weaknesses that formed earlier in the season. However, on high alpine slopes above where the rain crust formed, facets, and/or buried surface hoar may be susceptible to triggers.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow and wind have formed slabs that rest on a stout crust.  In some places a very weak layer of surface hoar may rest between the crust and new snow which is a prime setup for human triggered avalanches.
Good day to make conservative terrain choices.>This is NOT the time for big terrain.>Stick to simple well supported terrain without convexities and be aware of what is above you at all times.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 25th, 2014 2:00PM