Avalanche Forecast

Issued: Dec 13th, 2011 8:48AM

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

Avalanche Canada mpeter, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Wednesday: Expect a weak ridge to develop during the day, giving dry conditions. Clouds will build in the evening with the chance of flurries overnight. Winds should be light and westerly with temperatures reaching -5. Thursday: A chance of flurries with continued westerlies and afternoon temps reaching -5. Expect a ridge to build late in the day and winds to turn northwest. Friday: Dry and predominantly clear, with northwest winds and temperatures reaching -5.

Avalanche Summary

no new avalanches

Snowpack Summary

Up to 10cm of new snow has fallen since the 10th of December. This overlies surface hoar, surface facets, old windslabs and sun crusts (on steep south through west aspects). Winds have been sporadic in this period, with some strong northerlies intermingled with the more dominant light to moderate westerlies. There are isolated new soft slabs in immediate lee locations and some surface sluffing in more protected areas where the surface hoar is more prominent. Moving forward, the avalanche danger will increase as the load increases (either by new snow or wind). Be locally aware of changes and if obvious signs of instability are present (cracking, whumphing, recent activity on adjacent slopes) or rapid loading is taking place (heavy snowfall or strong winds) then scale down your terrain choices accordingly.Deeper in the snowpack there is a rain crust buried between 20-35cm. This crust extends as high as 2200m and some faceting (weakening) has been observed around the crust. Deeper still, the early November surface hoar remains a layer of concern. Buried 100-150cm it is unlikely to trigger, but consequences of triggering would be a large (up to size 3.0) destructive avalanche.

Problems

Wind Slabs

An icon showing Wind Slabs
Hard windslabs linger in isolated lee locations in the alpine.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Highly variable snow depths make this very difficult to predict. Weaker thin spots on convexities or around protruding rocks/clumps of small trees may be likely trigger locations for deeper avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 14th, 2011 8:00AM

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