Mount Sparrowhawk Avalanche
Snow conditions were: Wind affected. Weather conditions were: Cold. We rode: Alpine slopes, Sunny slopes, Open trees. We avoided: Convex slopes. Riding quality was ok.
Avalache Conditions: Whumpfing or drum-like sounds or shooting cracks.
Party of 3, 1 member stayed on Ridge at treeline to enjoy the strong sun and take some photographs. Other 2 skiers decided to make for the Reid/Sparrowhawk col. We decided to gain some height on westerly facing slopes via breaking of a new skin track. We would then traverse across and up to the col. Unfortunately on making the final kick turn prior to traversing, a large cracking sound was heard, followed by some movement within the snow. Looking up around 20m above us, the snow fractured around the line of exposed rocks. Stayed on our feet as long as we could before being transported downhill. Kept arms up above the moving snow and applied a swimming motion to stay on top. Slid for around 30-40m before the slide slowed to a stop on flatter terrain. Both skiers buried to waist, lost 1 pole, but otherwise uninjured. Taking back from the situation, I think we should have stayed lower in the bowl prior to ascending directly below the col. It appeared our trigger was from the windslab on top, stepping down onto weak basal layers in a shallow section of the pack. In hindsight, this should have been fairly obvious from our ascent route chosen, but I think we felt we were far enough away from the shallower section by the rocks that it would not have been an issue.
2 skiers skinning up bowl between Reid's Tower and Mt. Sparrowhawk intending to access the Reid/Sparrowhawk col, triggered an Avalanche on westerly facing slopes that were in shade at that current time. The snow on top was around 6" - 12" of hard windslab from the previous storm (13th - 14th March). My thoughts are that this particular trigger was the windslab stepping down onto the buried facets on a shallower section of the pack (there were rocks visible around 15m above our location).
Source: Avalanche Canada MIN