Avalanche Forecast

Issued: Jan 15th, 2017 3:36PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs.

Avalanche Canada mgrist, Avalanche Canada

Heavy (wet) snowfall and strong winds are a recipe for large destructive avalanches. Danger will increase in the south to HIGH on Monday as well.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

More snow Sunday - Monday... and beyond. This will be a stormy period for the Northwest. MONDAY: Sunday night all through Monday: 40 cm near Kitimat ; 10-20 cm near Terrace ; 20-30 cm near Stewart. Winds strong (60 Km/hr +) from the southwest. Freezing level 800m in the south and 1100m in the north. Alpine high temperatures -1 in the south and -5 in the north. TUESDAY: An additional 30 cm in the south and 15 cm in the north. Winds moderate to strong (40-60 Km/hr) from the south. Freezing level 1400m in the south and 1100m in the north. Alpine temperatures near +1 in the south and -3 in the north. WEDNESDAY: Another 15-30cm depending on your location. Freezing levels 1100-1300m. Winds moderate southwesterly. Alpine temperatures +1 to -3.

Avalanche Summary

Several storm slabs and loose dry avalanches were reported on a wide range of aspects Saturday.

Snowpack Summary

We've had a significant warming trend since the arctic outbreak, and a large storm snowfall gradient (15-30cm in the south ; 50-70cm near Stewart). The new snow fell with moderate to strong SW winds, and formed touchy soft slabs and wind slabs. Expect this new snow to bond poorly to all the windslabs (and a spotty layer of surface hoar and facets buried Jan 12th) that formed during last week's arctic outbreak conditions. The older wind slabs sit on a variable interface composed of hard wind slabs, weak surface hoar (Jan 5/6 layer) and faceted snow. If you're starting to think it's a dog's breakfast, you're right! With the recent new snow loading, the deeper slabs are expected to remain reactive, especially on southwest facing features near ridge crests. Deeper in the snowpack, the Christmas surface hoar layer (buried 70-120 cm) is still preserved in some southern areas and might still be reactive in sheltered areas and steep open features at treeline. Deeper weak layers (early December facets) have only been reactive in areas with thin snowpacks.

Problems

Storm Slabs

An icon showing Storm Slabs
Lots of storm snow sits on a complex mix of wind slabs, surface hoar and facets. Conservative terrain use is essential!
Use conservative route selection, choose moderate angled and supported terrain with low consequence.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Minimize exposure during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Jan 16th, 2017 2:00PM

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