Avalanche Forecast

Fair

Friday: Moderate NE winds at ridgetop. Freezing level at valley bottom. No snow. 1500m temp: -12Saturday: Light W/NW winds at ridgetop. Freezing level valley bottom. No snow. 1500m temp: -16Saturday: Light NW winds at ridgetop. Freezing level valley bottom. No snow. 1500m temp: -16

A natural cycle to size 2 was observed in the Castle backcountry on Wednesday. 

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.