Regions
South Coast Inland.
Fresh storm slabs will be primed for human triggers. Stick to simple terrain and stay well away from any large avalanche paths.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
THURSDAY NIGHT: Snow; 5-15 cm. / Moderate to strong, southwesterly winds / Low -3/ Freezing level 1200 m.FRIDAY: Snow, 10-20 cm. / Moderate to strong, southwesterly winds / High -3 C / Freezing level 1200 m. SATURDAY: Cloudy with sunny periods / Light, southwesterly winds / High -4 C / Freezing level 500 m.SUNDAY: Cloudy with flurries; 3-5 cm. / Light, southerly winds / High-14 C / Freezing level surface.
Avalanche Summary
No avalanches were reported in the region on Wednesday. However, fresh storm slabs reactive to human triggers are expected to form on Friday.
Snowpack Summary
The forecast new snow will cover a variety of snow surfaces. These include crusts on all but northerly aspects, wind-pressed surfaces on northerly aspects in the alpine, and a mixture of surface hoar (weak feathery crystals) and surface facets (sugary grains) in terrain sheltered from wind/sun at treeline and below.Around 30 to 50 cm down is a melt-freeze crust to mountain top on southerly aspects, a crust below around 1700 m on all aspects, and feathery surface hoar in areas sheltered by the wind/sun at treeline elevations. The remainder of the snowpack is currently well-settled and strong in most locations.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.