Avalanche Forecast
Issued: Dec 17th, 2011 9:07AM
The alpine rating is Wind Slabs and Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Freezing levels are uncertain on Sunday
Weather Forecast
On saturday night and into sunday morning 10-15 cm of snow is forecast for the region with moderate to strong southwest winds. Freezing levels should sit at about 1200m during this time.During the day on sunday expect slight clearing, light northwesterly winds and freezing levels dropping to surface. On monday the forecast calls for continued clearing, light northwesterly wind and freezing levels at surface.On tuesday, expect more of the same with trace amounts of snow.
Avalanche Summary
Recent observations include several easily triggered pockets of fresh wind slab in immediate lee terrain near ridge crests. The size and likelihood of avalanches should increase with saturday night's forecast weather.
Snowpack Summary
The early December dry spell left us large surface hoar and faceted powder on sheltered shady slopes, and a surface crust on sun-exposed slopes. They are now buried by soft slabs and more recent wind-transported moist snow and will continue to get an increased load over the forecast period. Assuming the structure of the old snow surface is preserved long enough for a sufficiently thick and cohesive slab to bury it, then a highly unstable situation should develop. Particularly where surface hoar and/or faceted crystals are associated with a weak crust. The mid and lower snowpack are generally well settled and strong, but faceted. Basal facets and depth hoar necessitate caution on wind-exposed slopes with highly variable snowpack depths, where this deep persistent weakness could be triggered from a shallow spot. Check out the Forecaster's Blog link below for more general snowpack discussion and good advice.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 18th, 2011 8:00AM