Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain on Saturday
Weather Forecast
Thursday: Mostly clear with increasing clouds in the afternoon. Freezing levels as high as 1500m, and moderate southwesterly winds. Friday: up to 15cm of snow with freezing levels around 1000m and strong southwesterly winds. Saturday: Another 20-30cm possible, especially for coastal areas, with freezing levels remaining around 1000m and strong westerly winds.
Avalanche Summary
Recent observations are limited to isolated human-triggered Size 1 fresh wind slabs. One was 20m wide by 20cm deep on a NE facing alpine slope.
Snowpack Summary
Dribs and drabs of new snow with associated winds are keeping wind slabs fresh and poorly bonded to the variable but predominately crusty 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. Weak facets may be lurking at base of the snowpack in shallow alpine areas, but there have been no recent reports of associated instabilities.
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.