Avalanche Forecast

Issued: Dec 13th, 2012 3:00PM

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

Avalanche Canada pmarshall, Avalanche Canada

Avalanche danger is expected to rise on the weekend in response to heavy snow and strong ridge top winds.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Synopsis: A brief weak ridge on Friday should result in drier conditions, but will quickly be displaced by a series of weather systems beginning on Saturday.Friday: A mix of sun and cloud with a chance of flurries. Freezing level around 800 m. Winds are light. Saturday: 15-25 cm of snow. Freezing level steady around 600-800 m. Winds increase to strong from the SW. Sunday: Moderate to heavy snow (20-25 cm). Winds remain moderate to strong. Freezing level around 600 m.

Avalanche Summary

Numerous natural and human triggered loose snow avalanches were reported on Wednesday. There were also a few reports of small human-triggered avalanches in wind loaded terrain. Clear weather on Wednesday revealed a few older natural avalanches up to Size 3 on northerly aspects in the alpine. These events may have released on the late November surface hoar layer.

Snowpack Summary

Recent winds have been stiffening the low density storm snow and forming reactive slabs. New snow falling on Thursday may be burying a thin layer of surface hoar in some areas. Below the recent storm snow weaknesses, the snowpack is well settled and strong. A layer of surface hoar that formed during late November has been found intact or decomposing in some locations down a meter or more. The early November crust/facet combination near the base of the snowpack seems to be dormant, at least in deep snowpack areas where it is buried too deeply by a stiff snowpack to be affected by light triggers on the snow surface.

Problems

Wind Slabs

An icon showing Wind Slabs
Expect to encounter touchy wind slabs below ridge crests, behind terrain features, and in cross-loaded gullies.
Avoid lee and cross-loaded terrain near ridge crests.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Dec 14th, 2012 2:00PM