Recently formed wind slabs have been slow to settle and gain strength.
Weather Forecast
On Tuesday and Wednesday morning expect a mix of sun and cloud and light northwest winds. By Wednesday evening a Pacific system will make its way inland bringing 5-10cm of new snow and strong southwest winds. Freezing levels will stay at valley bottom for the forecast period.
Avalanche Summary
On Monday, a skier triggered a size 2 wind slab avalanche at about 2250m in the Revelstoke backcountry. The individual was taken for a ride, but was uninjured. I expect recently formed wind slabs will remain sensitive to human triggering on Tuesday. There is also the ongoing possibility of triggering more destructive persistent slab avalanches in isolated terrain.
Snowpack Summary
Recent storm loading brings storm slab thickness to 20-40cm and up to 50cm in wind loaded areas. The recently destructive persistent weak layer from early January is now typically down 70-110cm in most places and has recently produced some large, destructive avalanches in the region. The layer is slowly getting harder to human trigger but is still quite reactive in snowpack tests and has the potential for wide propagations. In general, the lower snowpack below this layer is well settled and strong.
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.