Avalanche Forecast

Issued: Dec 13th, 2013 8:24AM

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

esharp, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

A warm front will push across onto the south coast late Saturday. Freezing levels will rise before the the trailing cold front crosses the province on Sunday. Monday with be a pretty benign weather day ahead of the next low pressure system expected early in the week.Tonight and Saturday: Expect snow to start falling Saturday morning. This will turn to rain at lower elevations as the freezing level rises through the day from 600m to 1200m. Snow accumulations at higher elevations will range between 10 and 15cm in the Cascades, Pemberton Icecap and the Hurley with only a dusting forecast for the Duffy. Southwesterly ridgetop winds will start as moderate but become strong later in the day.Sunday: Light precipitation will continue before tapering off overnight. Ridge top winds will slowly diminish later in the day. Freezing levels will drop slightly in the wake of the cold front.Monday: A brief break ahead of the next system is forecast with overcast skies, light southwest winds and freezing levels holding at 1000m.

Avalanche Summary

No recent avalanche have been reported

Snowpack Summary

Snowpack depths vary greatly across the region with 160cm at treeline in the Cascades but only 50cm along the Duffy. Terrain below treeline is still mostly below threshold for avalanche activity.The last system brought light accumulations across the region barely covering a variety of old surfaces: a crust exists wind scoured north and northeast slopes and surface hoar can be found in sheltered locations above 1900m. These layers could become reactive over the weekend as the overlying slab develops due to additional snow, wind loading and rising temperatures.A few crusts can be found near the ground, especially at higher elevations. The recent cold temperatures may have weakened the snow around these crusts - especially in alpine areas with a thinner snowpack such as moraine features.Overall the coastal snowpack is significantly thinner than the historical average for this time of year. 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 where supportive snow bridges have not yet developed.

Problems

Storm Slabs

SW winds will form soft slabs in the alpine and at treeline. The avalanche hazard will be lower in areas that receive less snow and will increase throughout the day as the wind strengthens and temperature increases.

Be cautious as you transition into wind affected terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>The snowpack on glaciers is shallow. Be cautious of hidden crevasses and un-supportive snow bridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Weakness at the bottom of the snow pack may be a problem in isolated thin and rocky areas at higher elevations such as glacial moraines.

Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 14th, 2013 2:00PM