Several parties have been surprised by dramatic whumphs on north facing fans below large terrain features recently. Evaluate the snowpack carefully before committing to any big lines.
Weather Forecast
Unsettled air pushed inland from a low pressure systems hitting the north coast will give several waves of snow flurries, with up to 15cm of accumulation by the end of the week. Wednesday: Cloudy with sunny periods. Afternoon flurries (up to 5cm). Treeline temps: Low -8 C. High -2 C. Ridge wind light SW. Freezing level: 2100m.
Snowpack Summary
Incoming new snow will be covering a strong surface crust on all aspects below treeline, and in to the alpine on solar aspects. A winter snowpack remains on N aspects treeline and above, with small pockets of windslab in lees, facets under an 20-50cm slab in isolated areas, and a weak base of facets and depth hoar in shallow snowpack areas.
Avalanche Summary
No new activity has been observed or reported.
Confidence
Forecast snowfall amounts are uncertain
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.