Avalanche Forecast

Issued: Mar 10th, 2016 7:33AM

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

pmarshall, Avalanche Canada

Northwest Coastal.

Caution is required in exposed wind-affected terrain on Friday.

Summary

Confidence

Moderate

Weather Forecast

FRIDAY: Cloudy with sunny breaks and a chance of flurries (2-5 cm). The freezing level is around 800 m and winds are moderate to strong from the SE. SATURDAY: Cloudy with sunny breaks and a chance of flurries. The freezing level is around 800-1000 m and winds are light from the SE. SUNDAY: Cloudy with sunny breaks. The freezing level is near 1000 m and winds are light.

Avalanche Summary

Sunny breaks in the northern part of the region on Wednesday led to a few natural cornice falls and slab avalanches up to size 3 on steep solar aspects. There were also reports of a few natural wind slabs up to size 2.5 from wind-loaded alpine slopes. Skier testing produced a few size 1 wind slabs in steep lee terrain.

Snowpack Summary

Cloudier conditions and moderate snowfall persisted in the southern part of the region on Wednesday, while norther sections saw sunny breaks and only light snow. Expect a surface melt-freeze crust in areas where the sun was a factor. Ongoing strong winds have shifted the new snow into hard or soft wind slabs at treeline and in the alpine, maintaining a wind slab problem on northerly aspects and scouring leeward slopes. Some areas are reporting a weak surface hoar layer near the base of the 50-70 cm of recent storm snow. An old crust buried in early February can now be found around 80-120 cm below the surface. This crust, which may coexist with small facets or decomposing surface hoar, recently produced sudden planar ("pops") results in snowpack tests. Although no recent avalanches were reported to have failed at this interface, I'd remain suspicious of this layer in steep, unsupported terrain at treeline and in the alpine.

Problems

Wind Slabs

Daily light to moderate snowfall combined with moderate or strong ridge winds have built deep and touchy wind slabs in lee and cross-loaded terrain.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Cornices

Cornices are reported to be large and weak. These could pop off at any time, but are more likely to fail with continued growth or during brief sunny breaks.

Extra caution needed around cornices with current conditions.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 11th, 2016 2:00PM