Avalanche Forecast

Issued: Jan 11th, 2017 4:39PM

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

Avalanche Canada swerner, Avalanche Canada

Wind is the critical factor and reactive wind slabs on a variety of aspects may be lurking.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Arctic air continues to be entrenched in the Lizard and Flathead region. The pattern will start to shift Thursday to a zonal flow, allowing Pacific frontal systems to make way into the Interior early next week. Little change is expected for the weekend.Thursday/ Friday/ Saturday: Cloudy with sunny periods accompanied by a slight alpine inversion and warmer temperatures by Sunday. Alpine temperatures near -15 and valley bottoms -20.  Ridgetop winds light-moderate from the West.

Avalanche Summary

A round of natural loose dry and storm slab avalanches up to size 1.5 were reported on Tuesday. Additionally, explosives triggered one size 1.5 storm slab on a northeast aspects at 2100 m elevation which was 15-20 cm thick. On Thursday, recently formed wind slabs may still be reactive to human triggering. With the winds recently switching directions, wind slabs should be expected on a variety of aspects.

Snowpack Summary

15-20 cm of recent snow has buried a variable snow surface which consists of wind scoured surfaces, old wind slabs in exposed terrain, surface hoar up to 20 mm in sheltered terrain, and/or widespread faceted old snow. Recent moderate winds from all directions is has redistributed some of this new snow on leeward slopes and behind terrain featu. Deeper in the snowpack, the mid-December persistent weak facet layer has been more prominent and reactive in the Corbin area than areas closer to Fernie. The layer is generally considered dormant right now but may wake up during the next storm or period of warming.

Problems

Wind Slabs

An icon showing Wind Slabs
Recently formed wind slabs may still be reactive to rider triggering. Wind direction has changed recently and wind slabs may exist on all aspects.
Avoid areas where the surface snow feels stiff or slabby.Use ridges or ribs to avoid pockets of wind loaded snow.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 12th, 2017 2:00PM

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