Solar radiation will rapidly and dramatically increase the avalanche danger on exposed slopes, with maximum effect latter in the day.
Weather Forecast
Cooling tonight with the freezing level rising to 1800m on Thursday and to 2100m on Friday. A westerly flow bringing snow flurries that may, by the weekend, provide another 20cm of snow in the alpine. Light wind will be south and westerly.
Snowpack Summary
Crusts exist up to 2200m on all aspects and extend higher on solar aspects. Above treeline wind slabs up to 65cm thick can be found in isolated locations. Bonding is generally good, however a graupel layer has recently been shown to shear with moderate force at the interface. Deeper weaknesses can be found near the base of the snowpack.
Avalanche Summary
No recent activity observed. A large cornice failure onto a easterly facing alpine start zone, known to be a frequent performer, failed to produce an avalanche. Limited older (>48hrs) size 2 activity from treeline and above is thought to have been triggered by solar radiation.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Friday
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.