Avalanche Forecast

Issued: Feb 3rd, 2016 8:14AM

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

triley, Avalanche Canada

Sea To Sky.

Stormy weather is coming, and avalanche danger will increase with wet and windy conditions.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Light snow overnight with moderate southwest winds and freezing levels around 600 metres. Light snow continuing on Thursday with increasing southwest winds and freezing levels rising up to about 1000 metres. Light snow Friday morning becoming heavy snow/rain in the afternoon as strong southerly winds push warm and wet air into the region causing freezing levels to rise up to at least 1500 metres. Heavy snow and strong winds continuing overnight into Saturday morning.

Avalanche Summary

Some sluffing reported from steep terrain on Tuesday. Reports from Monday include more evidence of the widespread large slab avalanche cycle associated with heavy loading from snow, wind and rain over the weekend. 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 may be found 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

Loose dry snow at higher elevations may be transported into pockets of wind slab in the lee of terrain features.

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 - Likely

Expected Size

1 - 3

Loose Dry

Loose dry snow may sluff in steep terrain.

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

Fresh cornice growth may fall off naturally with continued loading from wind and new snow. Fragile cornices may be easily triggered by traveling on adjacent terrain.

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

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Feb 4th, 2016 2:00PM