Avalanche Forecast

Fair - Due to variable snopack conditions

Thursday: Light snowfall ending in the afternoon / moderate to strong southwest winds / freezing level at 700mFriday: Mostly clear / light to moderate northwest winds / freezing level at surfaceSaturday: Mostly clear in the morning with a system arriving in the afternoon bringing light to moderate snowfall / light to moderate southwest winds / freezing levels rising to about 800m

On tuesday night several natural and explosives-controlled size 2 avalanches were observed in the region.On Saturday in the Bonnington Range several avalanche incidents occurred. The first reported was remotely triggered by a skier, it produced a size 3 slab avalanche from ridgetop. This slide was at 2200m on a North-North East aspect and ran 400m in length. There was also a skier remote size 2 from the same group. There were no involvements with these avalanches. Another group of skiers had similar observations from this mountain range. They triggered a skier remote size 3 from 100m away, additionally a size 2 sympathetic occurred. The size 3 crown depth was 50-120cms, 200m wide, and ran 400m. Both avalanches initiated from 1800m on S-SE aspects. The suspect layer possibly being the Mid December surface hoar/facet layer. I would normally not include observations from this far back; however, it points to the need to be aware of the variation in your local snowpack, and make observations while you travel.

On Tuesday approximately 15-25 cm of snow fell in the region. The system was accompanied by strong to extreme winds from the southerly quarter. Hard new wind slabs are now the primary concern in the snowpack.Over the weekend up to 35cms of new snow fell. This new snow came in denser that the previous, cold storm. This has been a recipe for continued storm slab instabilities as these slabs are reported to be quite reactive due to their poor bond on the cold snow interface below. Lower down is a crust that lies down 50-60cms and exists below 1900m. The bond with this crust appears to be quite good, however, on steep slopes this could easily act as a weak interface, potentially creating a layer for avalanches that initiate in the upper snow to step down to. Layers of concern deeper in the snowpack include a surface hoar/facet layer from mid-December and weak basal facets at the base of the snowpack in shallow snow areas. These layers have become less of a concern in the vast majority of locations. Last Saturday the mid- December layer is thought to have failed in several large avalanches that occurred in the Bonnigton Range. This is a lingering layer of concern that reflects low probability but high consequence. Snowpack depths in the region are around 240 cm.