Avalanche Forecast

Issued: Mar 4th, 2014 8:02AM

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

swerner, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair - Wind effect is extremely variable

Weather Forecast

A fairly benign weather pattern with continued outflow winds until Friday. The pattern will then change and the coastal areas will see light-moderate amounts of precipitation, rising freezing levels and strong SW winds.Wednesday: Sunny. Alpine temperatures near -12.0. Ridgetop winds light from the North. Slight alpine temperature inversion.Thursday: Sunny with some cloudy periods. Alpine temperatures -10.0. Ridgetop winds light from the North. Freezing levels valley bottom with a stronger alpine temperature inversion.Friday: Snow amounts 5-10 cm. Alpine temperatures -5.0. Ridgetop winds light - moderate from the SW. Freezing levels 800 m.

Avalanche Summary

Natural avalanche activity has tapered off and only sluffing from steep terrain has been reported. Over the weekend a minor natural avalanche cycle occurred in the northern part of region. Slab avalanches up to size 2 were reported from alpine and treeline cross loaded features. 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 avalanche.

Snowpack Summary

Cold arctic air has developed melt-freeze crusts on all aspects at lower elevations, and all but North aspects in the alpine. No recent reports of whumpfing or remote triggering on this weak layer of crusts and facets. Forecast strong Northeast outflow winds 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 may be large and destructive.

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

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Wind Slabs

Strong Easterly winds continue to scour slopes and develop hard wind slabs in areas that have snow available for transport.

Watch for areas of hard wind slab in steep alpine features.>Avoid travelling in areas that have been reverse loaded by winds.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Mar 5th, 2014 2:00PM