Avalanche Forecast

Issued: Dec 11th, 2013 8:00AM

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

chris gooliaff, Parks Canada

Glacier.

Surface sluffing has the potential to knock you, or your buddies below you, over. Pay attention to how much snow is moving with you!

Summary

Weather Forecast

Forecasted amounts of snow will be light in Rogers Pass today, with perhaps 5cm falling today and 5-10cm tomorrow. Temperatures continue to moderate from last week's deep freeze, warming to around -7*C in the alpine. Winds should continue to be light/moderate from the SW.

Snowpack Summary

25cm of low density storm snow sits over the December 8 surface hoar layer at lower elevations and over variable wind slabs up high. The November 28 surface hoar layer is down around 35-40cm over a facetted mid and lower snowpack. The November 12 surface hoar layer is down 60-110cm.

Avalanche Summary

Several size 1.5-2.5 slab avalanches were observed from the steep start zones off Mt Tupper and Mt MacDonald yesterday. Sluffing of the low density surface snow was observed in unsupported terrain, steeper than 35 degrees.

Confidence

Forecast snowfall amounts are uncertain

Problems

Loose Dry

The new, low density snow overlies a loose, facetted upper snowpack. Skiers and riders should expect fast sluffing in steeper terrain, which may gain mass if it entrains the underlying facets.

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: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

Variable soft and hard wind slabs are buried 25-30cm below the surface.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

The surface hoar layer from early November is buried 60-100cm below the surface. It is most likely triggered in shallow snowpack areas. If it does start to move, expect a large avalanche with nasty consequences.

Dig down to find and test weak layers before committing to a line.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 4

Valid until: Dec 12th, 2013 8:00AM