A storm hitting the eastern slopes of the Rockies is only expected to bring modest amounts of snow into BC. Avalanche danger will be greatest in eastern parts of the region that could receive up to 30 cm of snow by Wednesday afternoon.
Reactive storm slabs and wind slabs could form in parts of the region that receive >20 cm of snow on Wednesday. Elsewhere, be on the lookout for old wind slabs around ridgetops and in alpine terrain.
TUESDAY NIGHT: Flurries with 10-15 cm of snow near the Alberta border and a 0-10 cm around the Lizard Range, 50-70 km/h wind from the northeast, alpine temperatures drop to -16 C.
WEDNESDAY: Flurries with 5-15 cm of snow with the greatest accumulations near the Alberta border, 80 km/h wind from the northeast, alpine temperatures around -18 C.
THURSDAY: Flurries ease off throughout the day but still deliver another 5-10 cm of snow, clearing in the afternoon, 40 km/h wind from the northeast, alpine temperatures around -18 C.
FRIDAY: Sunny, light wind from the northeast, alpine temperatures around -15 C.
Avalanche conditions will largely depend on how far the storm hitting Alberta penetrates into the Lizard Flathead region. At this point, eastern parts of the region could receive up to 30 cm of new snow which will be enough for human triggered storm slabs. Western parts of the region, including the Lizard Range, may get very little snow.
Old wind slabs are still possible to trigger in alpine terrain. There were several reports of small wind slabs over the weekend including this MIN report from the Harvey Pass area on Saturday that describes several small human triggered slabs.
A storm hitting Alberta could bring 15-30 cm of new snow to eastern parts of the region by Wednesday afternoon while western parts of the region including the Lizard Range may see very little snow.
The snowpack is thin with many rocks and trees sticking out. The snowline starts around 1500 m, with about 40 cm of snow at 1700 m, and 50 to 100 cm of snow in the alpine. Two crusts have been reported in the middle of the snowpack. There is uncertainty about how the snow is bonding to these crusts, and they may act as a sliding layer for snow above them. Be prepared to back off to mellow terrain if you encounter signs of instability such as whumpfs or shooting cracks, which could indicate these layers are capable of producing avalanches.
