Although the danger has dropped to CONSIDERABLE, a very cautious approach is imperative. The mountains have hit the reset button and we need to do the same with our expectations of what is safe to ride.
Confidence
Fair - Due to limited field observations
Weather Forecast
Thursday: Cloudy, with a clearing trend late in the day. Expect alpine temperatures to reach -10 with light northerly winds.Friday & Saturday: Expect a mix of sun and cloud, with light northerlies turn to southwesterlies and alpine temperatures of -15.
Avalanche Summary
Natural and explosive triggered windslabs have released up to size 2.0. Poor visibility has obscured much of the higher terrain, so we have limited observations.
Snowpack Summary
The recent storm has deposited anywhere from 20-40cm of new snow. This has been accompanied by strong to extreme southwest winds, resulting in extensive windslab development in lee and open terrain. Due to the consistent winds, the slabbing extends well down onto slopes much lower than is normal. This new snow overlies significant snow depth and layer variabilities. Hard windslabs, hard pressed (windward slopes) snow and previous wind scour are all newly buried. In more sheltered areas the interface is small facets, surface hoar on sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. Snowpack tests on the surface hoar yield Sudden Planar results.The mid pack is well settled and strong. This overlies one or two crusts (location specific) with the higher crust being as shallow as 80cm below the surface. Concern lingers (unlikely) for triggering a deep slab avalanche in a shallow snowpack area or with a heavy trigger.
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.