Be aware of conditions that change with elevation and expect touchy fresh storm and wind slabs at higher elevations.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Saturday
Weather Forecast
FRIDAY: Unsettled conditions with isolated flurries, moderate becoming light southwesterly winds and freezing levels dropping to 1400 m.SATURDAY: Cloudy with flurries bringing another 2-5 cm overnight, light winds and freezing levels around 1000 m.SUNDAY: Cloudy with light flurries, light southerly winds and freezing levels around 1300 m.
Avalanche Summary
Reports from Wednesday and Thursday morning include continued natural and skier-triggered loose wet avalanche activity up to Size 1 on steep slopes. On Monday a natural Size 2 wind slab was observed on a northeast aspect at 2100 m failing down 40 cm. Explosives triggered a few Size 2-3 persistent slabs failing on the early February weakness down 50-60 cm. Touchy new wind and storm slabs are sensitive to light triggers and have the potential to step down and trigger persistent slab avalanches.
Snowpack Summary
Expect to find 20-30 cm of fresh snow blown into touchy wind slabs at higher elevations, and wet and cohesionless rain-soaked snow at lower elevations, which should soon freeze into a solid crust. Rapidly settling storm snow from last week is still bonding poorly to the previous snow surface from early February, which is now down 60-80 cm and includes a sun crust on steep sun-exposed slopes, faceted snow, as well as surface hoar on sheltered open slopes. The mid and lower snowpack are generally well settled and stable in deeper snowpack areas but may be faceted and weaker in shallower areas. The mid-December surface hoar/facet persistent weakness can now be found down roughly 150 cm. It has become inactive in the south of the region, but may still be lingering in the northern part of the region near Blue River and Valemount.
Problems
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.
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.