Date: Saturday, 18 February.
Time: Approximately 10:30 AM
Location: West Bowl Mount Cain, Main Gully, skiers left hand side at first rock outcrop on skiers left in descent.
Elevation: 1450m
Aspect: NW
Slope Angle: approximately 32-33 degrees.
Trigger: Skier accidental.
Size: Estimated as size 2 (Could bury, injure or kill a person. Approximately 100 tons of snow).
Fracture height: 10cm to 80cm.
Fracture width: Approximately 40-50m.
Failure plane: Persistent crust/facet.
Distance ran: full path, approximately 300m.
Bulletin hazard rating on the day: Alpine: Considerable, Tree line: Considerable, Below tree line: Moderate.
Bulletin Main Concerns on the day: Wind Slab, Persistent Slab.
Description:
The skier was part of a group and descended on his own while the others waited above. He skied in under the first rock out crop on the skiers left on descent of the main gully feature. The fracture initiated there and quickly propagated skiers left for 40-50m. The skier fell immediately and rode the full length of the avalanche to near the trees at the bottom of the run out. He sustained no injuries but was partially buried and lost his skis.
Notes:
Two other avalanches where observed adjacent to this area.
The first was triggered about thirty minutes previously in the adjacent “Sliders” feature to the skiers left of the main gully when a snowboarder entered from above. Second hand reports state that the snowboarder sustained facial injuries when he hit a tree while being swept down by the avalanche. Estimated size: 1.5 (Between relatively harmless to people and large enough to bury, injure or kill a person. Between 10 and 100 tons of snow.).
The third avalanche was a natural release that happened around mid day the same day further skiers left in the sliders feature. This appears to be the largest avalanche of the day in the west bowl estimated at size 2.5 and running the full length of the path. Mid day was about the time that temperatures spiked to near zero at tree line that day.
Information for this report was compiled from interviews with the person involved in the main gully avalanche and two others who made observations.
One persons account of some of the incidents that day can be found at http://citizenclass.cp-sms.biz/entries/snow/near-death-experiences.