Avalanche Forecast

Moderate - Due to the number of field observations on Sunday

An Arctic front pushes southward on Monday bringing cold, dry conditions for the next few days. A mix of sun and cloud is expected on Monday with light alpine winds from the northwest and treeline temperatures around -15C. Conditions are expected to remain similar on Tuesday and Wednesday with sunny conditions, light northerly winds in the alpine, and treeline temperatures dropping to around -20C.

On Saturday, natural storm slab and wind slab avalanches up to size 2.5 were reported in the region. These were typically 25-40cm thick and were mainly occurring on north and east aspects in the alpine and at treeline. On Friday, a snowcat was able to trigger three size 2.5 wind slab avalanches by pushing snow off a ridge into steep wind loaded start zones. These occurred on a west aspect at treeline in the Monashees. On Monday, the storm slabs that formed over the weekend are expected to remain reactive to human-triggering. These storm slabs are expected to be most reactive on north through east aspects in the alpine as a result of recent wind loading. Isolated persistent slab avalanches on the mid-November crust will remain an ongoing concern and appears to be a low probability, high consequence problem which likely would require a heavy trigger or triggering from a thin area.

The weekend storm system typically brought 30-60cm of new snow to the region with strong southwest wind in the alpine. The resulting storm slabs are thickest and most reactive in leeward features in wind exposed terrain. In some areas, the recent storm snow may sit over a layer of small surface hoar. There is some uncertainty regarding the distribution of this surface hoar in the region but it was reported in a couple locations in the Monashees west of Revelstoke. The mid-November crust is now typically down 1-1.5m in the snowpack. Test results on this layer have been highly variable ranging from sudden and easy to unreactive. While there has not been much avalanche activity on this layer yet, it has many professionals concerned. It will be important to track how this layer evolves, especially with the upcoming period of cold weather. Below the crust the snowpack is generally well settled and is reported to be moist at lower elevations.  The snowpack depth tapers off substantially below around 1700m elevation and many early season hazards are still a concern.