Avalanche Forecast Northwest Inland

Wednesday 6th February 2019

Avalanche Danger Ratings Wed 6th Feb 5:03PM Danger Ratings Alpine: Moderate Danger Ratings Treeline: Moderate Danger Ratings Below Treeline: Low Wind Slabs Wind Slabs

Avalanche Canada Forecaster: cgarritty

Date Issued:

Valid Until:

A bit of new snow won't add much to our wind slab problems, but it might make them trickier to see. Choose a supported line and treat lee slopes with extra caution.

Confidence

High -

Weather Forecast

Wednesday night: Cloudy with scattered flurries bringing a trace to 3 cm of new snow. Moderate northwest winds.Thursday: Decreasing cloud and easing flurries finishing with a trace of new snow. Moderate northwest winds. Alpine high temperatures around -9, cooler at lower elevations under a mild temperature inversion.Friday: A mix of sun and cloud. Moderate to strong northeast winds, increasing over the day. Alpine high temperatures around -15 and cooling over the day. Saturday: Sunny. Moderate to strong northeast winds, easing over the day. Alpine high temperatures around -13.

Avalanche Summary

Observations from Monday showed small (size 1) wind slabs releasing naturally from steep, wind loaded pockets in the Howson range.Numerous avalanches were triggered by skiers and naturally within the recent storm snow on the weekend. Check out this MIN report describing widespread slab activity.

Snowpack Summary

Strong northeast winds have redistributed a recent 20 to 40 cm of storm snow in exposed terrain, forming wind slabs. Recent cold temperatures have been transforming the surface of this snow into a lower-density layer of faceted (sugary) grains at all elevations. Collectively, this layer of faceting storm snow overlies previously wind-affected snow in the high alpine and a widespread melt-freeze crust elsewhere. In the central and northern parts of the region, it may sit on feathery surface hoar crystals in sheltered terrain at all elevations. In the south of the region, the remainder of the snowpack has been reported as well-settled.Around and north of Hazelton, 50 to 100 cm of snow may overly two weak layers of surface hoar or sugary faceted grains.

Wind Slabs Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Strong north winds have redistributed our recent storm snow. Expect to find still-reactive wind slabs in cross-loaded and lee terrain features near ridges.

Analyze slopes for patterns of wind loading as you transition into wind affected terrain.Avoid recently wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Aspects: East, South East, South, South West, West.

Elevations: Alpine, Treeline.

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