Concept of Evaluation of Avalanche

JR East currently has in place structural measures for disasters caused by earthquakes, rainfall, strong winds, and the like, as well as non-structural measures for those such as operation control, and such measures are implemented in a company-wide manner. For snow-related disasters, however, we rely much on technical experience on local characteristics of individual regions and lines. For avalanches too, individual workplaces take measures according to their own plans for securing against disasters and inspection patrols based on guidelines on slope management (1983 version) developed by the former Japan National Railways (JNR). As many years have passed since the development of those guidelines, workplaces have added their technical experiences to the basic interpretation of those guidelines, and as a result, response made varies between workplaces. From the perspective of disaster risk management, it is desirable that risk management be implemented under rules where response is unified. In this context, we put together a method of quantitatively evacuating risk of avalanches according to the basic flow of the guidelines on slope management (1983 version), taking into account recent glaciological findings, past research results, technical experience at workplaces, and technical evidence by data analysis in this research project. In that work, we attempted to quantify and incorporate into such risk evaluation the protective effects of structural measures of disaster prevention. This article will explain the method put together for evaluating avalanche risk level with an aim of applying that to slopes with a potential for avalanches, and it will report the results of risk level evaluation calculated by this evaluation method with for slopes along railway lines