Avalanche Forecast

Issued: Dec 16th, 2013 8:23AM

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

Avalanche Canada bcorrigan, Avalanche Canada

Precipitation and high winds have created touchy slab conditions in the alpine and at tree line.

Summary

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

Tuesday: Another large storm hits the Northwest with heavy precipitation and strong southwest winds. Freezing levels may spike again as the storm passes through.Wednesday: Pacific frontal system exits the area and moves off to the east. Freezing levels drop to valley bottom for most of the forecast area through the next few days as arctic air moves south.Thursday: Freezing levels remain at valley bottom as the arctic air pushes south between storms.

Avalanche Summary

Numerous size 2-3 avalanches have been observed in the bear pass area. These mainly occurred on north through east slopes that are lee to strong southwest winds.The warm new snow is likely not bonding well to the weak layers formed in early December. Heightened avalanche activity and conditions will continue through Tuesday. Lower elevations are experiencing moist or wet natural avalanches releasing at or near the ground. This will become less of a problem once the freezing levels start descending back down to valley bottoms. Lee slopes will be touchy at upper elevations until this storm snow gets a chance to bond.

Snowpack Summary

Heavy wet snow has fallen at upper elevations with freezing levels rising to 1500m during the last storm. Strong Southwest winds have transported the new snow creating storm slabs that sit above a weak layer formed during the last cold snap. Surface hoar, and  facets in the upper snowpack are now buried anywhere from 50 to 80cm from the surface by the recent storms.Earlier in the week, reports from the Shames area at 950m elevation suggested the mid and lower snowpack was composed of various faceted layers and a stiff 4 cm crust. Another crust can be found closer to the base of the snowpack. The recent precipitation will strengthen the snowpack at lower elevations, but may prove to be problematic with rapid wind loading at upper levels.

Problems

Storm Slabs

An icon showing Storm Slabs
Large amounts of precipitation with freezing levels up to 1500 M in the western portion of the region. Wind and storm slabs have been quite active during the storm cycle producing large destructive avalanches. Use caution in wind loaded terrain !
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Be cautious as you transition into wind affected terrain.>Minimize exposure during periods of heavy loading from new snow, wind.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Dec 17th, 2013 2:00PM

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