Insured loss estimation from wind and storm surge for a re-occurrence of typhoon vera

On September 26, 1959, super typhoon Vera struck Japan's Coastline in Wakayama Prefecture with sustained winds of 120 mph. A maximum storm surge of 3.89 m was recorded at Nagoya Port, which is located in Aichi Prefecture along the northern coast of Ise Bay. The levee and dyke system that was in place at the time to protect Ise Bay ultimately failed and flood waters extended inland some 20 km. Over 5,000 fatalities resulted, 568,000 homes were destroyed or damaged, and property losses exceeded 500 billion yen. Some areas remained flooded for more than 100 days afterward. Typhoon Vera remains the most costly weather-related disaster in Japan's history.

This paper presents hazard and loss results from both wind and storm surge for several simulations from Typhoon Vera and a worst case re-occurrence of Vera that could strike Ise Bay sometime in the future. Best track data from the Japanese Meteorological Agency (JMA) is used to define key characteristics of the storm. A stochastic model is used to identify plausible worst case typhoons in the future. An analytic Typhoon Wind Model is used to construct the surface winds field at 1 km resolution and 15 minute intervals. The storm surge simulations were performed with a version of the Princeton Ocean Model (POM) that includes a Wetting and Drying (WAD) feature.

Wind, surge, and current velocity outputs from the models are generated at half-kilometer resolution and interpolated to 50 meter resolution to compute storm damage from wind and flood to existing exposure. The loss estimations are based on simulated breaches in the existing levee and dyke system.