Avalanche Forecast

Issued: Jan 23rd, 2017 3:52PM

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

Avalanche Canada rbuhler, Avalanche Canada

For most of the region, isolated wind slabs are the main concern.If you are in far north of the region around Valemount and Blue River, a persistent slab problem exists and the Cariboos bulletin is more applicable. Click here for more details.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

A mix of sun and cloud is expected on Tuesday with light alpine wind from the north and treeline temperatures around -8C. A mix of sun and cloud is also forecast for Wednesday and Thursday. Alpine wind is expected to remain light from the north and treeline temperatures are forecast to be around -10C.

Avalanche Summary

On Sunday, a natural size 1.5 wind slab avalanche was observed in steep unskiable terrain on an east aspect at 2100 m elevation. Solar triggered loose dry avalanches up to size 1.5 were also observed on steep southerly aspects. In the far north of the region near Blue River, a snowmobiler triggered a size 3 persistent slab avalanche on a south aspect in the alpine which released on surface hoar down 100 cm. Check out the MIN post for more details. In the south of the region, skiers triggered a few size 1 wind slabs above 2100 m elevation. South of Mica in the Selkirks, explosives triggered one size 3 storm slab avalanche on a northeast aspect at 2300 m which stepped down to a deeper layer in the snowpack and ran full path breaking a mature tree. On Tuesday, lingering wind slabs are expected to be an isolated concern in steep and unsupported or convex wind loaded terrain features. In the far north of the region, a persistent slab problem exists. If you are recreating in the Monshees south of Blue River or Valemount, use the Cariboos bulletin for more representative conditions.

Snowpack Summary

30-60 cm of recent storm snow typically overlies the variable mid-January interface with the largest snowfall amounts in the north of the region. The buried interface consists of wind affected surfaces in exposed terrain, surface hoar up to 10 mm in sheltered areas, and/or widespread faceted old snow. The bond between the new snow and the old surface has generally gained a lot of strength with the colder temperatures that followed the storm but weaknesses may still be lingering, especially where surface hoar is preserved. Strong southwest winds during the storm had redistributed the new snow and developed wind slabs in leeward terrain features. Isolated moderate outflow winds may have more recently resulted in reverse wind loading.The mid-December facet/surface hoar persistent weak layer can be found buried 100-120 cm deep. This layer is now dormant in the south of the region but is still a real concern in the far north of the region in the mountains around Blue River and Valemount.  It is highly recommended to investigate this layer before committing to any large, unsupported features.

Problems

Wind Slabs

An icon showing Wind Slabs
Stubborn old wind slabs may still be reactive to human triggering in steep wind loaded terrain features. In some areas, moderate outflow winds may have caused reverse loading and formed thin new wind slabs.
Use ridges or ribs to avoid pockets of wind loaded snow.Avoid areas where the surface snow feels stiff or slabby.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 24th, 2017 2:00PM