Avalanche Forecast

Issued: Feb 1st, 2017 4:37PM

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

Avalanche Canada cam_c, Avalanche Canada

Touchy winds slabs are lurking below ridgecrests and behind 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

THURSDAY: Mainly sunny with light northeasterly winds. Freezing levels in valley bottoms with alpine temperatures reaching -15 C.FRIDAY: Increasing cloudiness with light snow flurries starting in the afternoon/evening. Light but gusty southwesterly winds and freezing levels remaining in valley bottoms with alpine temperatures reaching -10 C.SATURDAY: Cloudy with light snow flurries and light but gusty southwesterly winds. Freezing levels remaining in valley bottoms with alpine temperatures reaching -10 C.

Avalanche Summary

On 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. Skiers also triggered several wind slab avalanches on Monday up to size 1.5. On Sunday, a natural size 1.5 wind slab avalanche was reported near Invermere on a northwest aspect at 2600 m elevation which had a slab thickness of 50 cm. In the Dogtooth, a few small natural wind slab avalanches were observed which were 5-15 cm thick. A MIN report from the Quartz Creek area shows a sledder triggered size 2 wind slab avalanche. Click here for more details. Fresh wind slabs are expected to remain sensitive to human triggering, especially on steep and unsupported (convex) slopes. Winds have recently switched from south to north and wind slabs should be expected on all aspects in exposed terrain.

Snowpack Summary

5-20cm of recent snow with strong shifting winds resulted in wind slabs on a variety of aspects in wind exposed terrain. A sun crust is being reported on steep sun-exposed slopes. Surface faceting is also being reported as a result of the current cold temperatures. A persistent weakness buried mid January 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. It has generally stabilized but may be sensitive to triggering in isolated areas where buried surface hoar is preserved. Another surface hoar/facet persistent weakness buried mid-December may be found down 50-100 cm, but is generally considered dormant. However, a few storm slab and wind slab avalanches stepped down to this layer last week in isolated areas. This layer remains an isolated concern for shallow snowpack areas where the weakness is closer to the snow surface.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs are expected to remain sensitive to human triggering, especially on steep and unsupported (convex) slopes. Winds have recently switched from south to north and wind slabs should be expected on all aspects in 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 2nd, 2017 2:00PM