Avalanche Forecast

Issued: Jan 1st, 2017 4:49PM

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

shorton, Avalanche Canada

Cariboos.

Strong northerly winds have loaded many slopes and potentially re-awakened deeper weak layers. Conservative terrain selection remains critical.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

MONDAY: Sunny with cloudy periods, 15-25 km/h east winds, alpine temperatures around -20.TUESDAY: A mix of sun and cloud., 20-30 km/h northeast winds, alpine temperatures around -20.WEDNESDAY: A mix of sun and cloud, 20-30 km/h northeast winds, alpine temperatures around -15.

Avalanche Summary

On Sunday, several natural wind slabs were observed on all aspects and elevations during the peak of the winds. A skier also remote triggered a 70 cm deep wind slab on southwest-facing slope at treeline. Looking ahead to Monday, expect wind slabs to remain reactive to human triggers. The additional load may also make the persistent slab over the mid-December interface more reactive in thin snowpack areas.

Snowpack Summary

Strong northerly winds have formed thick and touchy wind slabs on leeward and cross-loaded features at all elevations. The 40 to 80 cm of new snow the region received between Christmas and New Years has been wind affected and will settle into a slab on south-facing slopes when the sun comes out on Monday. The mid-December facet/surface hoar interface can be found buried 50-100 cm deep. The interface has been showing signs of gaining strength in thick snowpack areas, but remains a concern in thin snowpack areas throughout the region. The lower snowpack is well bonded and features a thick rain crust near the ground.

Problems

Wind Slabs

With recent winds coming from a variety of directions watch for signs of stiff or slabby snow on less commonly loaded slopes. Denser slabs found on south aspect slopes could be made more unstable by the sun.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be cautious as you transition into wind affected terrain.Avoids areas where the surface snow feels stiff or slabby.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

50-100 cm of snow sits above a weak layer of facets from mid-December and has recently been reactive in parts of the region with thin snowpacks. Winds slabs may also step down and trigger this layer.

Avoid convexities or areas with a thin or variable snowpack.Avoid regrouping in runout zones.Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 2nd, 2017 2:00PM