Avalanche Forecast

Issued: Jan 31st, 2017 3:52PM

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

Avalanche Canada rbuhler, Avalanche Canada

Lingering wind slabs are expected to remain reactive in steep wind loaded terrain features.  Use extra caution as you transition into wind affected terrain and watch for signs of recent wind loading.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

A ridge of high pressure keeps the region cold and dry for the next few days. Wednesday and Thursday are expected to sunny with light northeast wind and treeline temperatures around -15C. Increasing cloud cover is expected on Friday in advance of a weak storm system which is currently forecast to arrive late Friday.

Avalanche Summary

On Sunday and Monday, several natural wind slab avalanches up to size 2 were observed throughout the region. These avalanches occurred on most aspects and were mainly in the alpine but a few were at treeline. Slabs were typically 10-30 cm thick. Skiers also triggered several wind slab avalanches on Monday up to size 1.5. One of these avalanches was remotely triggered from 40 m away.On Wednesday, recently formed wind slabs are expected to remain reactive to human triggering, especially on steep and unsupported or convex slopes. Winds have recently switched from south to north and wind slabs should be expected on all aspects.

Snowpack Summary

A few centimetres of recent new snow with strong shifting winds have formed wind slabs on a variety of aspects in wind exposed terrain. A sun crust is being reported on steep solar aspects. Surface faceting is also being reported as a result of the current cold temperatures. The mid-January interface is now down 20-50 cm and consists of buried surface hoar in sheltered areas, sun crust on south aspects, and/or widespread faceted old snow. The interface has generally stabilized but isolated weaknesses may still exist where buried surface hoar is preserved. The mid and lower snowpack are generally well settled and stable.

Problems

Wind Slabs

An icon showing Wind Slabs
Recently formed wind slabs are expected to remain reactive in steep terrain. Recent winds have been from a variety of directions and wind slabs should be expected on all aspects in wind exposed terrain.
Use caution in lee areas. Recent wind loading has created wind slabs.Avoid areas where the surface snow feels stiff or slabby.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 1st, 2017 2:00PM

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