Wind slabs can currently be found on almost any aspect. Expect those on steep southerly slopes to be especially touchy.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Big change is coming with significant snow (and some rain) through to Thursday. MONDAY: Mix of rain and snow (10-20 cm at higher elevations) beginning near noon. Winds strong from the southwest. Freezing level 1400m and alpine high temperatures to 0 Celsius. TUESDAY: Mix of rain and snow (up to 35cm at higher elevations). Winds moderate to strong (35-70 Km/hr) from the south. Freezing level 2000 metres with alpine temperatures to +1 Celsius. WEDNESDAY: Snow (15-25cm) throughout the day. Winds moderate to strong (35-70 Km/hr) from the south. Freezing level 1600m and alpine temperatures around 0 Celsius.
Avalanche Summary
Several skier (accidental) triggered Size 1 wind slabs were reported on S to SE aspects above 2000m on Saturday.
Snowpack Summary
We have wildly variable surface conditions due to wind and sun effect. The pleasant warm weather this weekend resulted in a sun crust on steep solar (south) aspects. Last week, strong winds 'reverse loaded' snow in the alpine and also affected treeline elevations too. Touchy wind slabs (5-40 cm thick) formed on southerly slopes near ridge crests and roll-overs. These slabs are the primary weakness of concern in the snowpack, giving easy sudden planar results in snowpack tests. Deeper in the snowpack, older snow is bonding fairly well to a variable surface consisting of a mix of soft wind slabs, hard wind slabs, sastrugi, faceted snow, and even some surface hoar. Snowpack layers below this interface are generally well bonded, and the lower snowpack is solid.
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.