Weather Forecast
Wednesday: Mainly sunny, with freezing levels in valley bottoms and moderate northwesterly winds. Thursday: Increasing clouds with a chance of flurries in the evening. Freezing levels rising as high as 1500m, and moderate southerly winds. Friday: 5-10cm of snow, with freezing levels around 1200m, and moderate southwesterly winds.
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 wind slabs are bonding poorly to the variable but predominately crust snow surface from last weekend's warm, wet, and windy weather. Recent compression tests on a wind-loaded treeline slope produced easy to moderate sudden collapse results down 65cm on surface hoar overlying faceted snow. 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
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.