Wind slabs may be lingering in the alpine. Use extra caution in wind loaded terrain.
Confidence
Fair - Due to the number of field observations
Weather Forecast
The ridge of high pressure continues to produce clear and dry conditions. Thursday should see a mix of sun and cloud. Freezing levels are expected to reach around 1500m as a warming trend begins heading into the weekend. Alpine winds on Thursday are expected to be moderate-to-strong from the NW. On Friday, similar conditions are expected with a mix of sun and cloud and moderate-to-strong NW winds in the alpine. However, freezing levels may reach over 2000m. On Saturday, freezing levels are forecast to remain around 2000m and increased cloud cover is expected.
Avalanche Summary
No new avalanches have been reported recently. Natural avalanches are generally not expected on Thursday but small human-triggered avalanches remain possible in isolated areas, specifically wind-loaded areas of the alpine.
Snowpack Summary
Up to 10 cm of new snow sits on the previous snow surface which was a mix of surface hoar, crusts, wind affected surfaces, and/or dry powder. Periods of moderate northerly winds have produced pockets of wind slab in exposed lee terrain. The most prominent snowpack features is a thick supportive crust around 10-30 cm below the surface. It extends up to around 2200m. Below this elevation the crust is effectively capping the snowpack, preventing riders from stressing deeper persistent weak layers. In alpine areas where the crust is not present or is less thick, it could still be possible to trigger a deep avalanche from rocky sun-exposed slopes, thin snowpack areas, or with a heavy load (i.e. cornice fall).
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.