Avalanche Forecast

Issued: Dec 10th, 2013 8:38AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Interior regions will start to see moderate amounts of snow, gradual warming and strong ridgetop winds as the warm front of the Pacific Frontal systems arrives on Wednesday.Wednesday: Cloudy. Snow amounts 5-10 cm. Alpine temperatures near -9. Ridgetop winds moderate from the West. Thursday: Cloudy with flurries near 4 cm. Alpine temperatures near -10. Ridgetop winds moderate, gusting strong from the West.Friday: Cloudy with snow mounts near 5 cm. Alpine temperatures -8. Ridgetop winds light from the SW. On Friday a weak ridge may stall precipitation later in the day, and bring some sunny breaks.

Avalanche Summary

No recent avalanche observations have been reported.

Snowpack Summary

Strong NE winds have reverse loaded and formed isolated wind slabs in the leeward side of SE through West aspects. Loose dry surface sluffing from steeper terrain may occur, so use caution near terrain traps like cliffs, and depressions.Widespread surface hoar development and surface faceting exists from the previous cold temperatures and is now getting buried by incremental snowfall amounts. Snowpack depths at treeline vary across the region, averaging 70-110 cm. In the Southern part of the region there is 40-70cm of new snow over the late-November surface hoar/ crust/ facet interface that may be reactive, especially in sheltered northerly aspects where the surface hoar was better preserved.In the Northern part of the region the lower/mid snowpack is fundamentally weak, composed of an early season crust (more prevalent on north aspects) and weak faceted crystals and depth hoar above and below the crust. This persistent slab may be stubborn to trigger, but if triggered have high consequences.

Problems

Wind Slabs

An icon showing Wind Slabs
Winds from the North have redistributed snow forming wind slabs in lee terrain. Wind slabs found on these aspects are not typical, and they may surprise you.
Avoid freshly wind loaded features.>Avoid traveling in areas that have been reverse or cross-loaded by winds.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
In deeper snow areas, it may be possible to trigger an avalanche on a layer of buried surface hoar. In shallower ones, watch for a weak sugary facet layer near the base of the snowpack.
Dig down to find and test weak layers before committing to a line.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 11th, 2013 2:00PM

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