Weather Forecast
Thursday: Light N wind. Alpine temperature near -11. No precipitation.Friday: Light NW wind. Alpine temperature near -12. No precipitation.Saturday: Light W wind. Alpine temperature near -14. Light snow.
Avalanche Summary
A widespread natural cycle of avalanches up to size 3 has been observed over the past two days. Many failed during rapid wind-loading on Tuesday night. Skiers have also been triggering numerous avalanches, including a size 2-2.5 slab which was triggered remotely from 30 m away. Many avalanches have been failing on surface hoar or facets below the storm snow.
Snowpack Summary
Deep storm snow overlies weak old snow surfaces including surface hoar (most prevalent at and below treeline), facets and sun crusts (found on some steep south to south-west aspects). There is a poor bond at this interface. In wind-exposed terrain, wind slabs and cornices have formed in the lee of ridges and ribs. Storm snow will take time to settle and stabilize, even after the weather improves and temperatures drop. A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack.
Problems
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.
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.