Avalanche Forecast

Issued: Feb 21st, 2017 3:27PM

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

triley, Avalanche Canada

Northwest Inland.

Watch for deep pockets of wind slab that have developed from recent storm snow as it is transported by the wind.

Summary

Confidence

Weather Forecast

Tonight: High overcast with some broken skies, a chance of flurries, moderate northwest winds and at least -12 in the alpine. Wednesday: Mix of sun and cloud with moderate northwest winds and close to -15 in the alpine. Thursday: Mostly sunny with a chance of strong northeast outflow winds developing. Friday: Clear with moderate to strong northeast winds and close to -20 in the alpine.

Avalanche Summary

Report on Tuesday of a size 2.0 avalanche on the "5000" run off Hudson Bay Mountain in Smithers. This was a visual report from town, the sliding surface is unknown but suspected to be the recent storm snow.

Snowpack Summary

10-15 cm of recent storm snow has been transported by the wind, and now sits on a variety of old surface conditions including isolated wind slabs, pockets of soft snow (5-10 cm deep), sun crusts, and surface hoar. A supportive rain crust exists below 1000 m. A layer of surface hoar that was buried on February 10th may exist 30-60 cm below the surface, but there's a fair bit of uncertainty regarding the reactivity and distribution of this layer. A stiff mid pack sits above weak sugary snow near the ground. Although possibly dormant, this basal weakness has the potential to produce very large destructive avalanches.

Problems

Deep Persistent Slabs

A weakness at the bottom of the snowpack is lingering and may be triggered in shallow snowpack areas or by the weight of smaller avalanches.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Avoid steep convexities or areas with a thin or variable snowpack.Avoid lingering in runout zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Wind Slabs

Recent storm snow has been transported by southwest winds into deep pockets of wind slab on lee slopes. If northeast outflow winds arrive, expect new wind slabs to develop on south through west aspects.

Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 22nd, 2017 2:00PM