Abstract
This study aims to conduct risk assessments for snowmelt-related landslide disasters and to propose a practical snowmelt estimation method that accurately assesses the landslide disaster risk. In recent years, landslide disasters have occurred during heavy rainfall events in many areas in Japan. In snowy areas such as Hokkaido, landslide disasters caused by snowmelt have frequently occurred. In this study, snowmelt was estimated by using three methods. One was a snow surface lowering measurement method, which was improved in its setting of snow cover density based on data gathered by using snow weight meters. Another was a heat balance method and the third was a degree-hour method. We estimated the soil water index by using the above three methods and examined whether it was possible to use snake curves to assess the risk of landslide occurrence. The examination clarified that landslide disaster risk can be assessed by using the snow surface lowering measurement method, which has been used in actual road management, when the snow cover density is set by using the method proposed in this study. As a result, we confirmed the superiority of the heat balance method in evaluating the risk of landslide disasters, and proposed improvement of the snow surface lowering method from the viewpoint of actual road management.
