Debris flow disaster in Atami, Japan, in July 2021

On the morning of July 3, 2021, a large debris flow occurred at the Aizome River in the Izusan district of Atami, Shizuoka Prefecture. The debris flow caused extensive damage, causing the death of 26 people, leaving one person missing, and damaging 128 houses (as of October 1, 2021). The Japan Society of Erosion Control Engineering set up the “Emergency Investigation Team of the Landslide in Atami, Shizuoka in July 2021” to understand the actual situation of the disaster and study the future countermeasures. The team conducted a field survey with the cooperation of Shizuoka Prefecture on August 12. This report summarizes characteristics of the debris flow as obtained from the field survey.