Danger levels are rising as a significant storm moves into the area overnight. Strong westerly winds will continue to build storm slabs through the day on Wednesday. Cautious route selection is strongly recommended.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
The weather forecast is uncertain, but the region could see between 15 and 20cm of new snow by the end of Wednesday with a further 15cm on Thursday. Temperatures for Wednesday should reach -7C and winds will be strong to extreme from the West.
Avalanche Summary
Isolated natural activity (both loose dry and storm slabs) was observed in steep Alpine terrain on N and E aspects up to size 1.0.
Snowpack Summary
Highly variable new snow amounts (2 to 4cm in valley bottom, 10 to 15cm at Treeline) overlie a wide variety of previous surfaces which include sun crust, surface hoar, facets, wind slab and bare ground. Storm slabs are forming in the Alpine and open areas at Treeline. The mid pack remains strong in most areas and the basal facets persist.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.