Avalanche Forecast

Issued: Feb 8th, 2017 4:32PM

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

Avalanche Canada mbender, Avalanche Canada

Use extra caution as you transition into wind affected terrain

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

THURSDAY: Cloudy with sunny periods / Light northeast wind / Alpine temperature -10 FRIDAY: Cloudy with flurries, accumulation 5-10cm / Moderate to strong southwest wind / Alpine temperature -5SATURDAY: Snow, accumulation 20-30cm / Moderate to strong southwest wind / Alpine temperature -1More details can be found on the Mountain Weather Forecast.

Avalanche Summary

No new avalanches were reported in the past few days. The most recent avalanche activity was reported on the weekend. This activity included skier triggered wind slab activity to size 1, explosive triggered wind slab avalanches to 2.5 and 3. Some of these avalanches in the Bear Pass area released on weaknesses near the base of the snowpack. In the northern most parts of the region near Bell2 or Ningunsaw, there are still reports as recent as Saturday of natural and skier triggered avalanches to Size 2.5 stepping down to basal facets in the alpine and at treeline.On Thursday, expect recently formed wind slabs to remain reactive to human triggering. Outflow winds have continued to add additional load to these wind slabs in places where there is still snow available to be redistributed. A basal weakness continues to drive a low probability/high consequence problem for shallow snowpack areas, especially in the north of the region.

Snowpack Summary

Widespread wind affected surfaces are being reported in exposed terrain including scoured surfaces, sastrugi, and hard wind slabs. In areas sheltered from the wind, the surface snow is reported to be faceting and surface hoar is developing. Below around 1100 m elevation, a rain crust can be found near the surface of the snowpack. Deeper in the snowpack, the mid-January surface hoar/facet layer is now typically down 70-100 cm. Recent observations suggest the layer has generally stabilized but isolated weaknesses may still exist, especially where buried surface hoar is still intact. Below this layer, the snowpack is generally strong and well settled. The exceptions are areas around Bear Pass and Ningunsaw where basal facets remain an ongoing concern, especially in shallow snowpack areas.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent strong to extreme outflow winds have formed hard wind slabs in leeward terrain features. These slabs are expected to remain reactive on Thursday and ongoing moderate outflow wind may continue to add additional load to these slabs.
Be aware of the potential for wide propagations due to the presence of hard wind slabs.Use increased caution in lee areas. Recent wind loading has created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 9th, 2017 2:00PM