Wind slabs are becoming more reactive in recent days. Generally poor ski quality, but fast travel and long days for those extended tours. Plan your trip to avoid sun-exposed slopes in the afternoon as we transition to Spring.
Weather Forecast
A mix of sun and cloud is expected on Tuesday with mild temperatures. Freezing levels should reach near 2000m. Winds will be out of the west at 30km/h at ridge top.
Avalanche Summary
On Saturday a skier triggered a size 2.0 full depth slide on a steep and shallow south aspect at 2700m. No injuries or burial, but the skier was carried approximately 400m down slope. The last 48 hours have seen an increase in wind slab activity as well. These have all been small, thin wind slabs triggered either naturally or by skiers in the alpine and open areas at treeline. Typically the trigger zones are steep and unsupported features.
Snowpack Summary
Widespread wind affect in alpine and open areas at treeline. Prominent in these areas are hard wind slabs, soft wind slabs, and breakable wind crusts. Reverse wind loading is also evident due to a recent wind event from the north. Sun crusts are dominant on solar aspects. The ski quality is reasonable on polar aspects below 2300m if you can find an area without tracks. The November facet/depth hoar layer is a live and well and has been responsible for a recent skier-triggered avalanche. See avalanche activity.
Problems
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.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.