Although unconfirmed, the starting zone is seen to be the top of the Backbowl sidewall (NW ridge from the summit) around 1250m elevation. The crown could not be identified but the avalanche type would have been a shallow surface slab avalanche. The victim has been found unconscious and CPA in the bowl at 950m at 10am on the 2nd Jan, 60cm under the surface and roughly 500m from the estimated starting zone. Although there was no clear signs of debris, sasa bamboo were unnaturally thick in the potential track area at 1100m, probably due to the avalanche scraping snow blocks off the slope. A mixed team of Hokkaido Police and Niseko ski patrollers did the search and rescue operation on the 2nd. One ski was found at 9:45am, followed by beacon search and identified the victim. He has been dug out and taken to Sapporo hospital by the police helicopter. The estimated causes of the avalanche are: 1. Skiing stimulation made unstable snowdrifts (developed by strong 25-30m/s ENE wind) collapse. 2. Sliding of depth hoar layer that formed and developed above 1200m area due to sun reflection effect.
According to the companion, the accident would have happened at 11:10am on the 1st Jan. 300m of altitude difference between the start and rescued point.
The whole slope seemed to have composed a big slab with partial hard-packed snowdrifts of windblown snow.
The cause of the accident would be that this person tried to ski Backbowl’s sidewall without considering the poor weather and strong wind consequences. No matter the amount of snow, avalanches happen in the right conditions.
We would like to offer all our sincere condolences to the victim and his family.
All access gates are kept closed due to insufficient snow; do not duck ropes to seek fresh lines. Mountain base 6am: -4℃, light snowfall and no notable development of snowdrifts. The snow in the trees seems good.
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