Wind slabs are likely to be encountered at upper elevations and may be reactive to human triggering, especially in lee features.
Confidence
Moderate - The weather pattern is stable
Weather Forecast
MONDAY NIGHT - Cloudy with clear periods / northwest winds, 10-20 km/h / alpine low temperature near -10TUESDAY - Mainly sunny with cloudy periods / southwest winds 10-30 km/h / alpine high temperature near -6WEDNESDAY - A mix of sun and cloud / southwest winds 10-20 km/h / alpine high temperature near -7 THURSDAY - Cloudy with sunny periods / southwest winds, 20-30 km/h / alpine high temperature near -5
Avalanche Summary
No new avalanches were reported on Saturday or Sunday.
Snowpack Summary
10-15 cm of cold smoke arrived by surprise on Sunday night! 10-30 cm of recent snow overlies a weak layer of sun crusts on south facing slopes, and surface hoar (feathery crystals) in sheltered areas. Previous strong winds had formed wind slabs over this interface. These are likely to be susceptible to human triggers, and they may be difficult to see now with the new snow on top of them.Large variability in snow depths still exists in the region, ranging from almost no snow to nearly 200 cm in some areas. For average snowpack areas, expect to find weak and sugary faceted snow around 50 to 100 cm deep, which extend to the ground. This weak bottom half of the snowpack was the culprit in several large avalanches in the region in the past few weeks.
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.