Kootenay Boundary

Good

Cool dry air out of the north brings light convective flow to much of the province Friday & Saturday. Friday: Sunny periods in the morning give way to broken cloud in the afternoon. Expect the occasional convective burst of snow. No significant precipitation is expected. Ridge top winds light out of the west. Freezing level tops out around 1700 m. Saturday: Freezing level starts at the surface, climbs to 1600 m, then returns to the surface overnight. Sunday: Flow switches from north to south Saturday evening resulting in slightly warmer temps Sunday. Freezing level climbs to around 2000 m. Winds light out of the east at treeline, moderate SW at ridge top.

Wednesday's snowfall produced the usual direct action avalanches. Sluffing was rampant in steep wind sheltered terrain while upper elevation wind exposed slopes produced both natural and human triggered small soft slab avalanches to size 1. A size 3 avalanche was observed on an upper elevation SE-E facing slope that likely came out Tuesday. Previous to Wednesdays's storm the region was very active with avalanches. Natural, explosive and human triggered avalanches were reported up to size 2.5. Remote triggering has also been observed.

Around 25 cm of snow fell Wednesday accompanied by moderate southwest winds which brings total snowfall since March 26th to 120 cm. This snow rests on a suncrust on solar aspects and a melt freeze crust on non solar aspects below 2000m. Reports from Wednesday afternoon indicate that the storm snow has been blown into soft slabs in upper elevation wind exposed terrain. On N aspects shears within the upper storm snow are tightening with the persistent warm temperatures, although a reactive layer down 40-50cm remains. The March 26 interface consists of a melt/freeze crust down around 100cm, on all aspects except true north treeline and alpine, where small surface hoar (5mm) is present in sheltered places. The bond at this interface is gaining strength, with lingering concerns on true south aspects where the crust is thickest and where the surface hoar lurks. At lower elevations, the consistent high freezing levels have kept the new snow heavy and moist. The deep, persistent early February surface hoar lingers in the snowpack giving sudden results in testing. Concern remains with heavy triggers (cornice), step down avalanches and rapid loading from intense precipitation, strong winds or sun.