Avalanche Forecast

Issued: Jan 16th, 2012 9:26AM

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

Avalanche Canada pgoddard, Avalanche Canada

Coquihalla area: The danger is CONSIDERABLE at treeline for Tuesday due to enhanced recent snowfall in that part of the region.

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain on Wednesday

Weather Forecast

Tuesday: 5-10cm snow. Strong westerly winds. Freezing level at valley floor.Wednesday/Thursday: Three weather models show very different outcomes. Anything's possible - from dry conditions to moderate (locally heavy) snowfall, with strong westerly winds and a slight rise in temperature. Confidence is poor. Check in tomorrow for an update.

Avalanche Summary

Skiers triggered slabs up to size 2 in the Coquihalla region on Saturday (incident reports here: http://www.avalanche.ca/cac/library/incident-report-database/view). In other parts of the region, storm snow was failing naturally and reacting easily to ski cuts. These results involved the storm snow and did not dig down to any deeper weaknesses.

Snowpack Summary

20-60cm dry recent snow has accumulated over the last few days (highest amounts around the Coquihalla). Increased wind and further snowfall is expected over the next few days, making new wind slab development very likely. Older wind slabs seem to have gained strength. A hard crust sits below recent storm snow layers. Recent snowpack tests showed stubborn or no results on this layer, which supports the weight of a person.Deeper in the snowpack, two persistent weak layers remain a concern only in thin snowpack areas (perhaps wind-scoured zones or relatively dry eastern ranges) and particularly in steep rocky terrain or sheltered terrain which has a thin snowpack. The two layers are surface hoar and/or facets associated with a crust from mid-December and sugary facets at the base of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs
New wind slabs are likely to form behind ridges and terrain breaks. Older wind slabs appear to be gaining strength, but should still be treated with caution.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Loose Dry

An icon showing Loose Dry
Loose, dry new snow can sluff easily in steep ground. It could trip you up or push you into a terrain trap.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 17th, 2012 8:00AM