Avalanche Forecast

Issued: Dec 15th, 2013 8:13AM

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

Avalanche Canada rbuhler, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Weak surface high pressure over the south coast will provide some breaks in precipitation for Monday. On Tuesday, a low pressure system will move onto the central coast. There is a lot of uncertainty with the weather models as to the effect that this system will have on the S. Coast Inland for Tuesday and Wednesday.Monday: Mostly cloudy with light precipitation, freezing levels around 1000m, moderate westerly alpine winds.Tuesday/Wednesday: Light to moderate precipitation possible at times, freezing levels may rise to as high as 2000m with the potential for a temperature inversion, moderate westerly alpine winds decreasing into Wednesday.

Avalanche Summary

No recent avalanches have been reported.

Snowpack Summary

Snowpack depths vary greatly across the region with 130cm reported at treeline in the Northern Cascades but only 50 cm along the Duffy. In general, the snowpack across the region is significantly thinner than average for this time of year. Terrain below treeline is still mostly below threshold for avalanche activity.20 to 30 cm of new snow is settling into a soft slab. Southerly winds have formed pockets of windslab in alpine lee features. Surface hoar from early in December can be found buried is sheltered locations above 1900m. On slopes that were scoured by early December's strong N winds the late November crust may have been exposed on the surface before the recent snowfall however in most locations it underlies up to 40 cm of week sugary snow.A few crusts can be found near the ground at higher elevations especially in rocky alpine areas with a thin snowpack.Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations. In glaciated terrain the forecast snow might just be enough to hide open crevasses.

Problems

Storm Slabs

An icon showing Storm Slabs
Use increased caution in wind-loaded areas. Recent westerly winds will form soft slabs at alpine and treeline elevations. In areas which received less new snow or where the snow has yet to settle into a slab, the hazard may be lower.
The snowpack on glaciers is shallow. Be cautious of hidden crevasses and un-supportive snow bridges.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Weakness at the bottom of the snow pack may be a problem in isolated rocky areas with a thin snowpack at higher elevations such as glacial moraines.
Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Dec 16th, 2013 2:00PM

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