Cooling temperatures will exert a slow stabilizing influence on the snowpack. For Saturday, human triggering of Large avalanches remains Likely in specific areas. Be especially cautious in areas of variable snowpack depth.
Weather Forecast
Saturday: An Upslope flow brings light snowfall and light - moderate Easterly winds. Temperatures fall, from -10 to -15.Sunday: A building ridge causes flurries to taper off, with some afternoon sun possible. -15, light winds.Monday: Return of the Westerlies! Expect: racing clouds, Strong Westerly winds, blowing snow, and rising temperatures.
Snowpack Summary
New snowfall is burying several layers of Hard Wind Slab at all elevations, formed by previous Extreme Westerly winds. In deeper snowpack areas, the Wind Slabs are sitting on a midpack of small facets, which have produced shears in tests. In thin snowpack areas, they are sitting on weak, large, developing Depth Hoar, producing Sudden shears.
Avalanche Summary
Explosives control work at neighboring avalanche operations have been producing Large avalanches daily in Wind exposed terrain, especially in areas that were shallow prior to recent wind loading from the West.Shooting cracks and Whoomphing were observed in pockets of Hard Wind Slab over Depth Hoar in Eastern (shallow snowpack) areas on Friday.
Confidence
Due to the number and quality of field observations
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.