Steady SW winds overnight will have created new wind slabs for travelers to avoid.
Weather Forecast
Mainly cloudy conditions today, with freezing levels holding near 1500m and winds dying down to light from the SW. Friday will see flurries becoming more organized with a sharp spike in snowfall by late afternoon. Freezing levels are expected to rise to 1800m with the snow, and winds will increase to moderate from the SW. .
Snowpack Summary
10cm of snow overnight has been redistributed by mod SW winds, forming slabs in lee features at tree-line and above. Below the new snow, a thick crust exists on solar aspects from the warmth earlier in the week. N aspects stayed dry but still sported heavy snow. The Jan 4th is down 90-130 and was producing sporadic sudden planar results.
Avalanche Summary
Natural activity slowed yesterday to a few loose avalanches to size 2.5 in the highway corridor. A field team up on the Dome Glacier observed old activity from Tuesday's dramatic warm-up. South and west aspects were cooked from 1700m and above and numerous point releases to size 1.5 were observed.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.