Avalanche Forecast
Issued: Dec 19th, 2011 9:15AM
The alpine rating is Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Good - -1
Weather Forecast
Tuesday: Light snowfall with 5-10cm of accumulation, freezing levels dropping to valley bottoms and moderate westerly winds. Wednesday: Mostly clear and dry with freezing levels in valley bottoms and light southeasterly winds. Thursday: Increasing cloud with flurries possible late in the day. Freezing levels remaining in valley bottoms.
Avalanche Summary
Recent observations include several artificially triggered Size 1, and one Size 2, wind slab avalanches from steep lee and cross-loaded alpine slopes. In the Diamond head area of Garibaldi Park, a natural Size 2.5 slab avalanche was observed on Sunday on a large steep wind-affected slope. Several natural loose snow avalanches up to Size 2 occurred in response to the rain/warming event on Saturday and sun-exposure on Sunday. Deep persistent slab avalanche activity on any basal layers is highly unlikely at this time.
Snowpack Summary
In exposed treeline and alpine areas touchy thin wind slabs are bonding poorly to a crust that formed after Saturday's warm temperatures and rain, and cornices are growing. Recent compression tests on a wind-loaded alpine slope produced easy to moderate sudden collapse results down 65cm presumably on last week's surface facets and/or surface hoar. The mid and lower snowpack are generally well settled and strong, but facets may be lurking at base of the snowpack in shallow alpine areas.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 20th, 2011 8:00AM