Avalanche hazard will fall as the temperature cools although the timing of how it does is difficult to forecast
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Wednesday
Weather Forecast
WEDNESDAY: sunny with scattered clouds, a freezing level of 2500m, light to moderate westerly winds. THURSDAY: partly cloudy, freezing level of 2000m, light westerly winds. FRIDAY: light flurries overnight as freezing levels fall to valley floor before rebounding to 2000m, mainly cloudy through the day, light southwesterly winds.
Avalanche Summary
A cycle of loose wet avalanches was reported on Monday and Tuesday.
Snowpack Summary
Moist snow can be found on solar aspects and a thin melt freeze crust may form on the surface overnight. Strong south west winds have resulted in widespread wind effect. Thick, stiff wind slabs can be found on north aspects in the alpine. Cornices have grown significantly. In the front ranges, the wind effect may be more extreme with widespread strastugi being reported in the alpine around Castle Mountain. In some areas you may find a supportive crust down 30cm that extends up to around 1900m. A layer of buried surface hoar can be found between 50 and 100cm down and remains a concern west of the Divide. The snowpack rests on a weak crust/facet layer from early December.
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.