The severe flood disaster by a typoon Rusa was occurred in the last year in Korea. The Rusa brought the rainfall of 870.5mm per a day in the city of Kangnung, Kangwon-do, Korea and this rainfall amount is 62% of the annual mean rainfall in this area. Our focus is to investigate the flash flood guidance and the sediment yield for the basins of small streams of Yangyang town in Kangnung area. Say, the flash flood guidance and the sediment yield by the Rusa are estimated and compared with the given informations obtained from the past flood events. As the results, the flash flood guidance and sediment yield in the study area showed much bigger values than the given informations and so we could know that the Rusa influenced the severe flood of the study area.