Avalanche Forecast

Issued: Dec 7th, 2014 8:05AM

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

Peter, Avalanche Canada

Northwest Coastal.

This Will be a Week of Dubyas: Windy, Wet and Warm! Expect increasing hazard and widespread natural avalanche activity by Tuesday.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Monday: Moderate rain or snow 15-25 mm. The freezing level could rise to 1800 m. Ridge winds could be pushing 100 km/h from the S-SE. Tuesday: Heavy rain or snow. The freezing level peaks near 2000 m and winds are still cranking from the S-SE. Wednesday: Cloudy with showers or flurries. The freezing level should start to drop, maybe as low 1500 m, but the strong southerly winds continue.

Avalanche Summary

A couple fresh natural windslab avalanches were reported from an area northeast of Stewart on Friday. These slides were observed on west facing slopes near treeline, and were an average of 20 cm deep. Similar activity is possible throughout the region.

Snowpack Summary

Conditions vary significantly throughout the region. The common theme is that the snowpack is generally shallow, quite facetted (sugary), and very wind affected. 5-15 cm of new snow now covers a mix of surface hoar or faceted snow in sheltered areas, and wind slab or ice crusts in exposed terrain. Strong NE-SE winds have created dense new wind slabs in open north or west-facing terrain. Old hard wind slabs may also be lurking underneath. The mid-November crust-facet layer is now 40-60 cm deep and continues to show easy to moderate shears in snowpack tests. Deeper in the snowpack, at 80 cm down there is another crust that is breaking down and becoming bonded to the surrounding snow.

Problems

Storm Slabs

Heavy new snow may not bond well to the underlying surface and could trigger deeper weaknesses in the snowpack. Extreme southerly winds could also create dense wind slabs well below ridge tops.

Be cautious as you transition into wind affected terrain 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

Likely

Expected Size

1 - 4

Loose Wet

Expect heavy loose wet sluffs in steep open terrain and in gullies.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 8th, 2014 2:00PM