抄録
Flush flood struck a party of boy's football team and killed one person. It occurred in the Yubiso River, Minakami town, Gunma Prefecture, at about 15:00, August 6, 2000. There was no rainfall around them. The authors made field surveys and analysis on rainfall data acquired by radar to clarify the reason for its occurrence. Conclusions are as follows. 1) The depth, the velocity and the peak flow rate of the flush flood are estimated to be 1-1.1m, 2.0-4.7m/s, and 18-51m3/s, respectively. 2) There was a rainfall of the maximum intensity of 20mm/hr at a part of the watersheds. 3) The result of the flood simulation shows that rainfall onto the partial watersheds can trigger the flush flood. 4) A deficiency of the calculated peak flow rate to the estimated one implies some contribution of snow melt to the flush flood.
