The presence of a buried weak layer requires discipline at this time. Start with small objectives and give the new snow a little longer to gain strength before pushing into more committing terrain.
Weather Forecast
Synopsis: A ridge of high pressure should be the dominant feature over the next several days. The only exception is on Saturday when a weak disturbance moves across the coast. Inland areas of the coast may only see a bit more cloud from this pulse. Temperatures should stay slightly below normal with daytime highs around -10 at treeline and winds generally light from the north. The sun should return on Sunday with temperatures starting to rise and the potential for an above freezing layer to form.
Avalanche Summary
There are reports of a widespread natural avalanche cycle from Tuesday night and Wednesday. Slab avalanches up to size 3 were observed, with many events occurring below treeline and failing on the early January surface hoar layer. There are also a couple reports of skier triggered avalanches up to size 2 and avalanches being triggered from a distance.
Snowpack Summary
40-80 cm of snow fell earlier this week, with the heaviest amounts in the Coquihalla area. Strong southwesterly winds produced dense wind slabs in exposed leeward terrain. Weaknesses exist within this recent storm snow as well as at the interface with the previous snow surface, which includes large surface hoar, facets, old hard wind slabs, or a sun crust. Recent compression tests on a north aspect below treeline gave several sudden planar (pops) results in the top 100 cm. No significant weaknesses have been reported recently below this in the mid snowpack layers. Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by heavy triggers in steep, shallow, rocky terrain where more facetting has taken place.
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.