Avalanche Forecast

Issued: Jan 31st, 2016 7:31AM

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

Monday: Cloudy with flurries and clearing in the afternoon. The freezing level is around 600-700 m and winds are light from the SW. 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. The freezing level is around 800-1000 m and winds are moderate from the S-SE.

Avalanche Summary

There was a report of a size 1 accidentally triggered slab avalanche near Whistler on Saturday. Skier testing and explosives control also produced several size 1 soft slabs and loose dry avalanches. On Friday, A few natural size 2-3.5 persistent slab avalanches were reported near Whistler. Some may have started as loose wet slides that stepped down and triggered deep slabs. All of these slides were from slopes near treeline (1800-2000 m). These likely occurred during the height of the storm on Thursday night.

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.

Problems

Wind Slabs

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

Avoid freshly wind loaded features.>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

1 - 3

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.

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

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

Possible

Expected Size

1 - 4

Valid until: Feb 1st, 2016 2:00PM