Avalanche Forecast
Issued: Nov 25th, 2011 9:21AM
The alpine rating is Persistent Slabs, Wind Slabs, Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - -1
Weather Forecast
Up to 30 cms of snow is expected for saturday accompanied by strong southwesterly winds. Freezing levels are expected to rise to 1500m. The system will continue through sunday bringing another 20-40 cms of snow. Winds are expected to remain strong but switch to north/northwest with freezing levels dropping to surface late in the day. A ridge should develop through sunday evening bringing mostly cold and clear conditions for monday.
Avalanche Summary
Explosives control in the region has produced numerous size 2 and 3 avalanches suspected to have stepped down to both of the facet/crust interfaces. Recent weather has limited the ability to make field observations, but there has probably been wide-spread natural activity as well due to recent snow and wind.
Snowpack Summary
The snowpack sits at approximately 150 cms just below treeline. At treeline and above, expect variable snow depths with much deeper wind deposits. In the lower snowpack there is a crust/ facet layer just above the ground that has been reactive to explosive testing in the region. In the mid snowpack, there has been widespread surface hoar observed at all elevations although reactivity on this layer seems to be decreasing. A more persistent weakness of facets with an associated crust can be found in the mid snowpack from 40-70 cms above the ground. This weakness exists at treeline and into the alpine where it is sensitive to human triggers and has a high propensity to propagate fractures. There's been over 120 cms of new snow since Sunday. Fluctuating freezing levels and varying wind and precipitation intensity during the recent storms has probably resulted in various storm snow weaknesses.
Problems
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 26th, 2011 8:00AM