A complex series of avalanche problems exists, conservative decision making and route selection is necessary.
Weather Forecast
A weak ridge builds Wednesday giving a break in the wind and snowfall.Wednesday: Clear periods and isolated flurries. Trace-5cm of snow. Alpine Low -10 C, High -9 C. Ridge wind moderate gusting strong from the West. Freezing level at valley bottom.Later in the week a Westerly flow will give alternating waves of flurries and clear periods.
Snowpack Summary
Wind slabs continue to build in exposed lee features. Storm slabs formed with 40cm of snowfall over the weekend. These problems sit on a recently developed rain crust 30-60cm deep. A persistent slab up to 200cm thick sits on the Halloween Crust, low in the snowpack. This crust can be found up to 2,700m depending on location.
Avalanche Summary
No avalanche patrol today. Explosive control work on highway 93 yesterday produced avalanches up to size 2.5. These avalanches released as newly formed wind slabs up to 70cm thick as well as one persistent slab up to 150cm thick releasing on the Halloween crust.
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.
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.