Avalanche Forecast

Issued: Dec 9th, 2014 8:15AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is low. Known problems include Storm Slabs, Persistent Slabs and Loose Wet.

ccampbell, Avalanche Canada

Sea To Sky.

Warm, windy and wet weather is expected to result in natural avalanche activity and increased avalanche danger.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Continued heavy rain, or wet snow at alpine elevations, is expected for Wednesday with strong to extreme Southerly alpine winds and freezing levels hovering around 2000 m. Thursday could see around 20 cm of fresh snow with light to moderate southeastery alpine winds and freezing levels as low as 1500 m. Friday is looking mostly dry with a mix of sun and cloud, light winds and freezing levels down around 1000 m.

Avalanche Summary

Reports from Monday include small skier-controlled wind slabs on leeward alpine slopes. Natural avalanche activity is likely with heavy loading from snow, wind, and rain.

Snowpack Summary

Heavy rain, wet snow and wind has formed new storm slabs and is overloading previous weaknesses buried within the snowpack, such as crusts and associated facets. While at treeline and below, the upper snowpack is becoming saturated, loose, and cohesionless. The snow pack depth drops significantly below treeline with essentially no snow below 1600 m.

Problems

Storm Slabs

Heavy snow and wind is expected to form weak slabs at alpine elevations, especially on Northwest-Northeast facing slopes below ridge crests.

Be alert to conditions that change with elevation and avoid wind loaded slopes near ridge crests.>Expect conditions to deteriorate. Assess conditions continually as you travel and be prepared to change plans.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 4

Persistent Slabs

Heavy and rapid loading from snow, rain, and wind could be enough to wake up persistent weak layers and produce large avalanches.

Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Loose Wet

Expect heavy loose wet sluffs in steep open terrain and in gullies. Although not expected to be large avalanches, they could knock you off your feet and have serious consequences if terrain traps are below.

Be aware of party members below you that may be exposed to your sluffs.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 10th, 2014 2:00PM