Simulation of the tornado hazard in the U.S

On average more than 1000 tornado touchdowns hit the continental US every year, causing significant human and economic losses. In order to manage tornado risk, we need to assess tornado hazard, the subsequent damage, and the resulting loss. The paper presents a methodology for tornado hazard assessment, which is an important step in the management of risk. For this purpose, a simulation approach is used to infer the characteristics of future tornadoes from those of past events. The paper first develops the probability distributions of the following tornado parameters needed in the simulation: rate of occurrence, relative frequencies of different Fujita scales, length, width, direction, location, and wind speed at touchdown. Then, an approach for generating tornado events using the Latin hypercube method is presented. The method is applied to obtain simulated databases. These databases are first used to check convergence on the underlying parameters. The databases are then used to study the convergence of average annual loss as well as losses that are exceeded with specified probabilities.