Avalanche Forecast
Issued: Dec 1st, 2012 9:14AM
The alpine rating is Storm Slabs and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Poor - Timing, track, or intensity of incoming weather is uncertain on Tuesday
Weather Forecast
The recent weather pattern continues, with a very persistent deep low off the coast driving a moist, mild SW flow over the region. Moderate accumulations are expected through the forecast period, accompanied by moderate S-SW winds. Sunday: Fzlvlâs 1200 m, snow amounts 5-10 cm, ridgetop winds SE 15-25 km/hr, alpine temps -4.Monday: Fzlvlâs 1200 m, snow amounts 8-15 cm, ridgetop winds S 35 km/hr, alpine temps -4.Tuesday: Fzlvlâs 1700 m in the am then falling to 900 m in the afternoon, snow amounts 10-15 cm, ridgetop winds S 30 km/hr, alpine temps -3 falling to -8.
Avalanche Summary
Explosive testing produced numerous size 1-1.5 slab avalanches on NW-N aspects. All instabilities reacting within the storm snow.
Snowpack Summary
Storm slabs and fresh wind slabs have loaded a variety of weak surfaces. These (now buried) surfaces consist of large surface hoar, a thin sun crust, and surface facets. Below this, the mid-pack seems to be fairly settled, strong and bridging instabilities that may exist deeper.Under the mid-pack (90-150 cm down) sits the early November facet/ crust persistent weakness. Recent snowpack tests have shown sudden collapse (or "drops") results on the early November facet/crust deep persistent weakness, but because this weakness is so close to the ground in most areas, any associated avalanche activity will likely be limited to slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, glaciers, etc.). Areas that are most susceptible to trigger this deep persistent weakness are shallow, thin and variable snowpack deposition spots.To view a recent snow pit profile from the Spearhead Range, check out the Wayne Flann Avalanche Blog.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 2nd, 2012 2:00PM