The meteorological condition for larger avalanches at Senjojiki Bowl in Japanese Central Alps

Abstract

The Senjojiki Bowl has a typical avalanche terrain consisting of8 avalanche tracks. During the last 25 years 16 alpinists and ropeway workers in total have been killed by avalanches. Since no reliable avalanche warning is issued by the Meteorological Agency, the ropeway company and an alpine guide has collected data on avalanches in the bowl since 1987 forthe safety oftheir guests. Using the data over the last three winters, we have analyzed the meteorological conditions leading to larger avalanches descending. It was Dund that the larger avalanches occurred only under the Dllowing simple conditions: l. cold snow storm type in high-winter, 2. warmer snowy type in high-winter, 3. wet snowy type in late winter and 4. rain storm type.