Avalanche Forecast

Issued: Mar 9th, 2013 8:32AM

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

Peter, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Tuesday

Weather Forecast

Sunday: A mix of sun and cloud. The freezing level is around 600 m during the day. Winds are moderate from the northwest. Monday: A mix of sun and cloud. The freezing level is around 600 m. Winds are light from the west. Tuesday: Light snow. The freezing level is around 500 m. Winds increase to moderate or strong from the southwest.

Avalanche Summary

Recent observations include one cornice triggered size 3 slab avalanche on a steep northeast aspect and a couple rider triggered size 1 wind slabs in exposed lee terrain.

Snowpack Summary

Widespread surface hoar growth and near surface faceting continues with clear and cool weather. Foot penetration has reduced to about 25 cm as the recent storm slab continues to settle. The west of the region is reporting a very well settled snow pack at all elevations. The East parts of the region have reported a shallow weak snowpack with areas of basal facets. Strong southwest winds have formed touchy wind slabs in exposed terrain in the lee of ridges, gully side walls, and behind terrain features. There are a variety of old interfaces now down 60 - 100cm which include facets, crusts and isolated pockets of surface hoar.

Problems

Wind Slabs

Thin new wind slabs may develop in exposed lee terrain on Sunday. Older wind slabs are becoming more stubborn to human triggers, but may release with larger triggers (cornice fall, multiple people on the same slope).

Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Large and weak cornices may fail, especially during periods of warming or solar radiation. A cornice fall could trigger a slab on the slope below.

Give cornices a wide berth when travelling on or below ridges.>Avoid steep slopes below cornices.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 10th, 2013 3:00PM