Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Wednesday: Snow amounts up to 15 cm arriving by the am. Light snow near 5 cm before noon. Ridgetop winds 30km/hr from the South. Treeline temperatures near -11. Thursday: Snow amounts 5-10 cm. Ridgetop winds moderate from the West. Treeline temperatures near -8. Possible solar influence in the afternoon if clouds break. Friday: A strong westerly flow brings light snow amounts. Strong ridgetop winds from the West. Freezing levels at valley bottom.
Avalanche Summary
Reports of natural activity seemed to dwindle on Monday. One natural size 2 occurred on a SW aspect @2400m. The crown was 40-50 cm deep, 40 m wide, and ran 300 m in length. Few, small size 1 skier triggered, and explosive triggered avalanches were reported on steeper, convex terrain features, and gully features. With forecast snow and wind, I suspect avalanche conditions will remain touchy, and susceptible to rider triggers through the forecast period.
Snowpack Summary
Due to switching winds, wind slabs can be found mainly on N-NE aspects and S-SW aspects in the alpine on exposed slopes at treeline. Reports indicate the new wind slabs are not bonding well to the southerly scoured, sun crust surfaces. The total settled storm snow is near 60cm and sits over a variety of old surfaces. These include melt-freeze crusts at lower elevations and spotty areas of surface hoar in sheltered treeline areas. Where they exist, they may act as sliding layers. Easy shears persist in the new storm snow down 25-40 cm with sudden planar results. The mid and lower snowpack is well bonded and strong.
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.