An examination on debris flow warning and evacuation system based on GIS (geographical information system) was developed to reduce human injury or death from debris flow due to heavy rain. The system examination was done in Ooshima County of Yamaguchi Prefecture where debris flow occurred in June, 1979. The geological composition of this area is granite. A developed model using a personal computer can issue information about the rainfall and the danger of debris flow occurrence. It also has a damage assumption simulation function to warn against high torrents of danger. Because the judgment of warning and evacuation was completely visual, the system proved to be effective.
