Avalanche Forecast

Issued: Jan 11th, 2017 4:44PM

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

jlammers, Avalanche Canada

Northwest Inland.

Weak, sugary snow at the bottom of the snowpack remains a primary concern. This is especially true in large, steep, and rocky alpine features with variable snowpack depths.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

Thursday: Light flurries / Strong Westerly winds / -10 in the alpineFriday: 2-5cm of new snow / Extreme southwest winds / -9 in the alpineSaturday: 3-8cm of new snow / Extreme southwest windsÂ / -5 in the alpine

Avalanche Summary

On Tuesday, a skier accidentally triggered a size 2 wind slab on a 34 degree southwest facing slope at treeline. This avalanche occurred a few kilometres east of the Kispiox river valley. No other new avalanches were reported.

Snowpack Summary

10-20 cm of new snow fell last weekend. Observations have been limited, although the few reports we've received suggest these accumulations have been shifted into wind slabs at treeline and in the alpine. Snow depth at treeline varies from about 1 m in most areas to 2 m in deeper snowpack areas in the south and west of the region. The shallow snowpack areas mostly consist of weak facetted or sugary grains beneath hard slabs. These hard slabs may produce surprisingly long fractures resulting in large avalanches, and in some instances they may step down to weak faceted snow crystals near or at the ground. In addition to the facets, a thick layer of buried surface hoar may be found 30-40 cm below the surface. There is another persistent weakness that formed during the early December cold snap which is now about 50-70 cm deep.

Problems

Deep Persistent Slabs

In most areas this is a lower probability, high consequence scenario and requires a conservative approach to larger terrain features. Avoid likely trigger spots such as steep and rocky areas with a shallow snowpack.

If triggered the wind slabs may step down to deeper layers resulting in large 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.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

Strong to extreme winds may redistribute any remaining loose surface snow into fresh wind slabs, adding to an ongoing wind slab problem. Wind slabs may step down to deeper weak layers resulting in surprisingly large avalanches.

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.Avoid areas where the snow feels stiff or slabby.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 12th, 2017 2:00PM