Avalanche Forecast

Issued: Jan 3rd, 2017 4:21PM

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

Avalanche Canada cgarritty, Avalanche Canada

Recent wind slabs will be gaining strength but may become unstable with solar radiation on Wednesday.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

Wednesday: Sunny. Winds light from the northeast with occasional strong gusts. Freezing levels to 200 metres and alpine temperatures to -2.Thursday: Cloudy with sunny periods. Winds light to moderate from the west. Freezing level near valley bottom with alpine temperatures to -3.Friday: Cloudy with scattered flurries and up to 5 cm of new snow. Winds moderate from the southeast. Freezing level rising to 400 metres with alpine temperatures of -2.

Avalanche Summary

Ski cutting in the North Shore mountains on January 1 produced one size 1 wind slab avalanche 10 metres wide and 20 cm deep. Shooting cracks were propagating up to 2 metres ahead of ski tips on wind loaded features, suggesting touchy conditions at the time. While we normally expect a short life span these kinds of instabilities on the South Coast, cold temperatures may be preventing our current wind slabs from bonding to underlying snow at the usual rate.

Snowpack Summary

Strong northerly winds have redistributed loose snow from recent storms into wind slabs behind exposed terrain features on southerly aspects, including both southwest and possibly southeast slopes. Approximately 95 cm of well-settled storm snow lies on the surface and has bonded well to the underlying snow. While snowpack tests have revealed no significant instability within the storm snow, the spatial variability of wind slab instabilities may be a limiting factor. Aside from wind slab instabilities in the upper snowpack, the mid and lower snowpack are considered to be well settled and stable.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs were recently formed on south to west aspects behind exposed terrain features. Slabs found on south-facing slopes could become more unstable when the sun is out.
Minimize exposure to sun exposed slopes when the solar radiation is strong.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 4th, 2017 2:00PM

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