Avalanche Forecast

Issued: Feb 27th, 2017 4:32PM

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

Avalanche Canada cam_c, Avalanche Canada

Watch for isolated wind slabs in unusual places, as northerly winds have reverse-loaded southerly aspects and undermined cornices.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

TUESDAY: Mainly cloudy with flurries bringing up to 10 cm of new snow, beginning in the afternoon. Winds beginning light to moderate from the southwest, increasing to strong over the day. Freezing level to 500 metres with alpine temperatures of -10 C.WEDNESDAY: Mainly cloudy with scattered flurries bringing 5-10 cm of new snow, beginning in the afternoon. Winds moderate to strong from the southwest. Freezing level around 600 metres with alpine temperatures of -9.THURSDAY: Mainly cloudy with 15-20cm of fresh snow. Moderate to strong southwesterly winds and freezing levels around 1300 m.

Avalanche Summary

Reports from the weekend include several skier triggered Size 1-2 wind slab avalanches up to 20 cm deep. These have generally been described occurring in the immediate lee of ridge features where recent southwesterly winds promoted new slab development. One observation of a Size 1 wind slab stands out for its mention of a remote trigger (10 metres away) and a 40 cm crown fracture. It should be noted that aggressive terrain selection may have been a contributing factor to a few more recent avalanche observations.

Snowpack Summary

Strong northerly winds have been redistributing 10-30cm of recent storm snow, into soft slabs as deep as 65 cm, which are poorly bonded to a weakening crust that extends into alpine elevations. In exposed alpine areas, winds have scoured down to this crust, which formed mid-February. Low temperatures have been responsible for faceting at the snow surface and in the upper snowpack. The mid and lower snowpack are well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Touchy wind slabs are lurking below ridgecrests and behind terrain features on all aspects in exposed terrain.
Be cautious as you transition into wind affected terrain.Avoid areas where the surface snow feels stiff or slabby.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 28th, 2017 2:00PM

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