Regions
Northwest Coastal.
Watch for signs of instability at upper elevations and be cautious around steep convex slopes where wind slabs or buried surface hoar may still be reactive.
Weather Forecast
TUESDAY: Cloudy with increasing flurries throughout the day and 1-3 cm of new snow, light west wind, alpine high temperatures around -7 C.WEDNESDAY: Mix of sun and cloud, light wind, alpine high temperatures around -5 C.THURSDAY: Cloudy, light wind, alpine high temperatures around -5 C.
Avalanche Summary
On Sunday, the only notable avalanche activity was from explosive control that produced several size 2 wind slabs. These occurred at 1500 m on west-facing slopes that were loaded by recent outflow winds.On Saturday, skiers triggered a few small size 1 avalanches on a 20 cm deep surface hoar layer at treeline elevations.A widespread natural avalanche cycle occurred last week. The cycle produced numerous size 2-3 storm slab avalanches and a few very large historic avalanches (size 4+) in deeply wind-loaded areas along the Skeena corridor. Following the natural activity, explosive control on Thursday produced more large and very large avalanches, but by Friday explosive testing produced mostly small avalanches.
Snowpack Summary
Surface snow consists of thin sun crusts, soft faceted snow, and wind damaged snow on a range of aspects in exposed terrain. In sheltered areas at treeline and below, 20-30 cm of snow sits over a layer of surface hoar that has been reactive to skier traffic. A few deeper interfaces may have been reactive during last week's storm, but have become much harder to trigger since. These include layers of sun crust, facets, and isolated surface hoar buried 50-100 cm below the surface. Deeper in the snowpack, around 150-200 cm down, you'll find a crust/surface hoar layer from January which still has the potential to be triggered from a thin snowpack spot, or with a large trigger like cornice fall. Basal facets may be found near the bottom of the snowpack in colder and drier parts of the region, such as in the far north.
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.