Avalanche Forecast

Issued: Feb 27th, 2014 8:25AM

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

triley, Avalanche Canada

Northwest Coastal.

Don’t let your guard down! The deeply buried weak layer may continue to be well preserved on shaded aspects. More info in the new blog post!

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

Overnight and Friday: The alpine inversion along the coast is expected to end overnight. We should see below freezing temperatures at all elevations during the day with Easterly winds in the alpine and strong Northeast outflow winds near the coast. Mostly clear with a chance of high thin cloud during the day.Saturday: Clear and cold with strong Northeast winds and alpine temperatures around -17. Very strong outflow winds near the coast.Sunday: Clear and cold with strong Easterly winds and alpine temperatures around -20.

Avalanche Summary

Moist or wet loose snow avalanches up to size 2.0 have been reported from Southerly aspects during periods of strong solar radiation. A couple of loose snow avalanches in motion triggered a 30-50 cm dry slab up to size 3.0. North aspects in the alpine continue to be the most likely slopes for triggering the February weak layer where it may be well preserved and allow for long fracture propagations resulting in very large avalanches.

Snowpack Summary

Strong solar radiation and warm temperatures have resulted in moist surface snow on all but shaded North aspects. Moist or wet loose snow has been releasing naturally from steep Southerly aspects. The early February weak layer continues to give moderate to hard sudden planar shears in snow profile tests down 50-100 cm in the North and down 100-150 cm in the South. No recent reports of whumpfing or remote triggering on this weak layer of crusts and facets. Forecast strong Northeast outflow winds may continue to develop wind slabs in areas that still have snow available for transport. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region. Cornices are also large and may become weak if northerly winds start to undercut them.

Problems

Persistent Slabs

North aspects in the alpine are the most likely slopes for human triggering the February weak layer. Avalanches releasing on this deeply buried persistent weak layer my be large and destructive.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Use conservative route selection, stick to moderate angled terrain with low consequence.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Wind Slabs

Forecast strong Northeast outflow winds may develop new wind slabs in areas that still have new snow available for transport. Large cornices may become undercut by changing wind directions.

Avoid travelling in areas that have been reverse loaded by winds.>Avoid freshly wind loaded features.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Feb 28th, 2014 2:00PM