Warming on Friday may have an adverse effect on snow stability, particularly on slopes that face the sun.
Confidence
Moderate - Freezing levels are uncertain on Friday
Weather Forecast
THURSDAY NIGHT: Light snow, 2 cm or so.FRIDAY: Sunny. Strong southwesterly winds. Freezing level around 1800 m. Light snow Friday night.SATURDAY: A mix of sun and cloud. Winds becoming light to moderate southwesterly. Freezing level around 900 m.SUNDAY: Flurries. Freezing level rising to around 1800 m. Moderate or strong southwesterly winds.
Avalanche Summary
No new avalanches have been reported in the region, but rugged travel conditions at lower elevations have lately been discouraging travel in the alpine, where the bulk of our current avalanche danger resides.
Snowpack Summary
About 20-25 cm of new snow has buried previous snow surfaces that ranged from soft power to hard wind slab and sun crust. Strong winds have likely been aggressively forming storm slabs and wind slabs with the new snow at higher elevations.Beneath the new snow and old surface, the snowpack has a thin, weak structure, with the bottom half of the snowpack composed of weak facets and crusts. This basal layer has not been active, but terrain features like smooth alpine bowls with variable snowpack depths are still suspect given this snowpack structure. Currently only 30-90 cm of snow can be found in alpine areas and much less at lower elevations
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.