Avalanche Forecast

Issued: Feb 2nd, 2016 8:10AM

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

Avalanche Canada ccampbell, Avalanche Canada

Large persistent slab avalanches should still be on your radar if you're heading into the Duffey Lake or other areas in the north of the region.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Friday

Weather Forecast

WEDNESDAY: Cloudy with light snow 3-5 cm. The freezing level is at valley bottom and winds are moderate from the S-SE. THURSDAY: Cloudy with light snow. The freezing level could rise to 1000-1200 m. Winds also rise to strong from the SE-SW. FRIDAY: Moderate precipitation starting Thursday evening with up to 20cm of total accumulation and freezing levels as high as 1500m.

Avalanche Summary

Reports from Monday include evidence of natural avalanche activity on Sunday in the Duffy Lake area with observations of several recent storm slab avalanches up to Size 2. On Sunday, there was a report of a size 2 wind slab avalanche that was remotely triggered by a skier in the mountains north of Pemberton. It was triggered from a thin snowpack area and released on a steep cross-loaded slope about 50 m away. Nearby, a cornice fall also triggered a size 1.5 slab on the wind-loaded slope below.

Snowpack Summary

In the south, 40-70 cm of recent storm snow sits on a widespread and generally supportive rain crust that was buried on Jan. 28. The bond to the crust appears to be fairly good but at least one notable storm snow weakness was observed 10 cm above the crust. Fresh pockets of wind slab may also form in immediate lee features. The combination of heavy storm loading, rain, and warm temperatures likely flushed out the mid-January persistent weakness in most areas in the Cascades. Further north, generally 20-40 cm of dry storm snow overlies the late-Jan rain crust below around 1800-2000 m. Above this elevation the new snow sits on settled storm snow or previously wind affected surfaces. Fresh pockets of wind slab are likely in exposed lee terrain. Where it still exists, the mid-January surface hoar layer is between 60 and 130 cm below the surface. This persistent weakness could be lingering on higher elevation slopes that did not previously avalanche and triggering remains a concern.

Problems

Wind Slabs

An icon showing 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

Likely

Expected Size

1 - 3

Loose Dry

An icon showing Loose Dry
Cold dry snow could sluff easily in steep terrain.
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 - Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Buried persistent weaknesses may have been destroyed in most areas, but remain cautious in high elevation terrain (particularly in the north of the region) where this problem may be lingering.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Feb 3rd, 2016 2:00PM