Avalanche Forecast

Issued: Feb 1st, 2016 7:42AM

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

pmarshall, Avalanche Canada

Sea To Sky.

Enjoy the much improved riding conditions but keep an eye out for terrain traps where the consequences of being caught in a small sluff or slab could be severe.

Summary

Confidence

High

Weather Forecast

Tuesday: A mix of sun and cloud. The freezing level remains near 500-600 m and winds are light and variable. Wednesday: Periods of snow 10-20 cm. The freezing level is around 800-1000 m and winds are moderate from the SW-SE. Thursday: Cloudy with light snow. The freezing level is near 1000-1200 m. Ridge winds are moderate from the SW.

Avalanche Summary

Skier testing and explosives control on the weekend produced several size 1-1.5 soft slabs from immediate lee features and loose dry avalanches on steep slopes. There were also reports of a couple size 1 accidentally triggered wind slabs from steep leeward alpine slopes.

Snowpack Summary

Up to 50 cm of dry new snow sits on 60-80 cm of moist settled snow from last week's warm storm system, or a rain crust below around 1800 m. Expect to find pockets of fresh wind slab in exposed lee terrain and the potential for loose dry avalanches on steep open slopes. Cornices are also becoming large and potentially weak. Where it still exists, the mid-January surface hoar layer is between 100 and 180 cm below the surface. The combination of heavy storm loading and warm temperatures has likely flushed out this weak layer in most areas. However, there is still some uncertainty regarding the sensitivity and distribution of this persistent avalanche problem, especially at high elevations in the north of the region where it remains reactive in snowpack tests (hard to initiate but sudden "pops" results).

Problems

Wind Slabs

Triggering fresh soft wind slabs is possible in exposed lee terrain near ridge crests, especially on steep unsupported slopes.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Cold dry snow could sluff easily in steep terrain. Additionally, loose wet sluffs are possible on steep sun-exposed slopes if the sun pokes out.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornice falls can be destructive by themselves, but can also be a trigger for surprisingly large avalanches on the slope below.

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

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Feb 2nd, 2016 2:00PM