Large Slope Disaster at Hakusan District in Japan and Estimation of Risk by Rockfall

A large rockfall disaster on Hakusan Shirakawa-go White Road occurred on a forest road in Ishikawa Prefecture on December 14, 2018. This important only road between Ishikawa prefecture and Gifu prefecture during 4 and half years could not be used. Fortunately, it was fully opened at May 20, 2023. Firstly, this disaster is explained in detail. Subsequently, the rockfall simulation method is introduced that had been developed by the authors. The method is applied to this real slope. The results of the risk evaluation of rockfalls on a road have been concretely shown. A rock shed is located on the road as a protection structure against rockfalls from the steep mountain slope. Finally, the current extent of the risk for rockfalls on the road considering the rock shed been shown.