New Statistical Approach to Select Coastal Flood-Producing Extratropical Cyclones from a 10,000-Year Stochastic Catalog

Extratropical cyclones (ETCs) are major storm, flood-producing events along the northwest European coastline. To evaluate the storm surge risk covering a return period over as many as 10,000 years (0.01% annual exceedance probability) in this region, a stochastic catalog was developed by perturbing historical European ETCs. Numerical simulation of the storm surges generated with an entire 10,000-year stochastic catalog; however, is computationally expensive. Also, not all the stochastic ETC events are flood-producing storms. We propose an efficient statistical approach to filter the stochastic catalog by estimating the storm-surge elevation and total water level at tide gauges and then selecting only the nonnegligible flood-producing coastal events. The proposed approach reduces the number of stochastic storms that need to be numerically simulated by 78%, thereby saving computational resources for high-resolution numerical simulations of flood-producing storms.