Typhoon Roke was the 15th typhoon of the 2011 West Pacific typhoon season, making landfall near Hamamatsu City in the Shizuoka Prefecture on September 21 as a weak category 2 typhoon with maximum sustained winds of 85 knots. The storm moved quickly across Honshu and the center of Roke exited the island northeast of Iawki City in the Fukushima prefecture. EQECAT estimates that insured losses from this event will total between $300 and $600 million.
The storm brought winds and rainfall as it briskly traversed approximately 300 miles across Honshu, Japan, impacting the Kansai, Chubu, Kanto and Tohoku regions. Tropical storm-force winds and rainfall affected the Fukushima area; site of the nuclear power plants that were damaged in the March Tohoku earthquake. Significant flooding has been reported from Nagoya to Sendai.
Damage in central Japan is from high winds and rain. After landfall, the center of Roke moved across central Japan at an average translational velocity of 35 miles per hour. A high-translational velocity influences the wind patterns by making the areas of highest winds to the east of the storm track. The winds in Suruga Bay and the southern-most portions of the Izu Peninsula and southern Chiba were exposed to typhoon-force winds. With Mount Fuji between the storm center and the Tokyo metropolitan area, the winds in Tokyo were mostly tropical storm force. The fast translational velocity of the storm reduced the amount of time the storm affected land, and rainfall accumulations were not as high as initially feared. Maximum rainfall accumulations of 16 inches (400 mm) were recorded in central Honshu near the Hamamatsu landfall location, and rainfall accumulations of 8 inches (200 mm) were observed near Fukushima.
Although Roke affected a large part of Japan, the insurable damage is expected to be concentrated in coastal areas of the Aichi, Mie and Shizuoka Prefectures. Direct wind damage is expected to be concentrated in the Shizuoka Prefecture, and flood damage is expected to be widespread. The port city of Nagoya observed significant rainfall and more than 1,000 buildings were reported to have been flooded.