Purcells

Fair - Timing, track, or intensity of incoming weather system is uncertain

Synopsis:  An intense frontal system with subtropical moisture is just now arriving on the BC coast. Warm air preceding the Pacific frontal system has already arrived pushing freezing levels up to 2000 metres in some parts of the forecast area.Tonight: Cloudy with flurries and trace to 10cm of precipitation. Strong SW winds and freezing levels climbing to 1700m.Sunday: Cloudy, snow flurries, possibility of 5 to 10 cm of snow, winds gusting to strong at ridge tops, freezing levels may climb to 2000m.Monday: Mix of sun and clouds, trace of precipitation in the forecast, light to moderate winds at ridge tops, freezing level drops to around 1500m. Tuesday:  Sunny with cloudy periods, no precipitation in the forecast, light winds at ridge top, freezing level down to around 1400m.

Storm slab avalanches continue to be reported running naturally. Most of the storm snow avalanches are size 1.5-2.0, however one was reported to be size 3.0 where the storm slab is now 80 cm thick. Explosives control released some large avalanches down to the early February persistent weak layer. There were also a couple of accidentally triggered storm slab avalanches, one that buried a sledder on a northwest aspect in the alpine. Expect natural avalanche activity to continue over the weekend with the continued forecast of new snow and wind.

Recent snowfall amounts have been highly variable throughout the region. In some deeper snowpack areas over 80cm of storm snow overlies a weak surface hoar layer that has been preserved in sheltered areas. A sun crust exists on solar aspects and and there are wind slabs in exposed terrain. On lee slopes these accumulations have been pushed into much deeper deposits by generally moderate southwest winds. Warming has added cohesion to the slab and wider propagations can be expected. At lower elevations rain has likely moistened snow surfaces. There is ongoing concern for a mix of weak surfaces which were buried on February 10th. This persistent interface lies between 60 and 160cm below the surface, and includes surface hoar, well developed facets and a mix of hard surfaces which remain widespread at all aspects and elevations. In some areas destructive avalanches are still a very real concern with ongoing reports of natural triggering, whumpfing and sudden/easy snowpack test results. The mid and lower snowpack are generally strong and well consolidated. Weak basal facets exist in many areas, but triggering has now become unlikely.