Avalanche Forecast
Issued: Feb 20th, 2012 8:50AM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Tonight and Tuesday: Moderate snowfall - 5-10cm tonight and an additional 10-15cm tomorrow. Winds increase to moderate-strong from the west. The freezing level (FL) is near valley bottom tonight rising to 1200m on Tuesday. Wednesday: Continued light to moderate snowfall - 5-10cm. FL dropping to 800-1000m. Winds should be moderate-strong from the west-northwest. Thursday: Cooler and drier under a brief ridge of high pressure. FL dropping to around 500m.
Avalanche Summary
There are several reports of natural and skier triggered avalanches up to Size 1.5. These avalanches occurred in wind affected terrain in the alpine, or on steep convex shaped features below treeline. The size and likelihood of avalanches will increase as the new snow settles into a more cohesive slab.
Snowpack Summary
Wind slabs continue to grow in exposed terrain in response to moderate W-SW winds. 15-40cm of low density snow overlies the Feb. 9 weakness, which includes surface hoar and/or a crust. This surface hoar layer may be widespread in some areas, while others have reported it being confined to shady aspects at treeline and in the alpine. A melt-freeze crust has developed on solar aspects at all elevations, and on all aspects below about 1600 metres. The mid-pack is generally well settled. There is some concern that large loads like cornices may trigger the Jan. 20th facet layer. Some shallow snowpack areas may continue to have a weak layer of basal facets near the ground.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 21st, 2012 8:00AM