Avalanche Forecast

Issued: Feb 22nd, 2017 3:20PM

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.

Changing wind directions may develop new wind slabs on Thursday.

Summary

Confidence

High -

Weather Forecast

Tonight: Mostly clear with moderate northerly winds and alpine temperatures around -15. Thursday: Mix of sun and cloud with strong northerly outflow winds and alpine temperatures around -17. Friday: Clear with strong northeast outflow winds and alpine temperatures around -15. Saturday: Overcast with flurries or light snow and moderate to strong northwest winds.

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Wind Slabs

Changing wind directions may develop new wind slabs on south through west aspects. Old wind slabs may continue to linger on other aspects.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 23rd, 2017 2:00PM