During the passage of Typhoon 0918 (Melor) over southern Honshu in Japan on 7 and 8 October 2009, strong winds with extremely high turbulence fluctuations were observed over Shirataki Mountain and the surrounding mountains in Shimonoseki, Yamaguchi Prefecture, Japan. These strong winds caused damage to wind turbine blades at the Shiratakiyama Wind Farm owned by Kinden Corporation. In order to investigate the causes of the blade damage, the airflow characteristics from the time of the incidences are first simulated in detail with the combined use of the WRF-ARW mesoscale meteorological model and RIAM-COMPACT® LES turbulence model. Subsequently, in order to evaluate the wind pressure acting on the wind turbine blades, an airflow analysis is separately performed for the vicinity of the blades with a RANS turbulence model. Finally, the stress on the blades is investigated using the Finite Element Method (FEM) with the RANS analysis results as the boundary conditions.