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Abstract

Single extreme events can affect multiple countries/ states simultaneously, which weakens the capacity of the emergency response systems. Although understanding the spatial dependencies of extremes is crucial for accurate risk analysis, little is known about how these dependencies change over time. This study quantifies the seasonal and decadal variations of the spatial dependencies of extreme skew surges along the coasts of Europe, North America, the Gulf of Mexico, and the Caribbean Sea. We use water level information from tide gauge measurements and a 39-year reanalysis dataset. We find that the spatial footprints of the extreme skew surges vary in size and location at decadal time scales in the Gulf of Mexico and the Caribbean Sea. For example, we detect a high correlation of extreme storm surges along the west coast of Florida at the beginning of the century. The dependencies weaken toward the end of the century and the spatial footprint shifts northward, toward the Mississippi coast.Seasonal changes are observed in Europe, the Gulf of Mexico, and the Caribbean Sea. We investigate the weather patterns (sea level pressure and 10-m wind speed) that drive the seasonal changes in the spatial correlations of skew surges. The International Best Track Archive for Climate Stewardship (IBTrACS) is used to exclude tropical cyclone events from the weather patterns, which are analyzed separately. Four representative weather patterns are identified that characterize the seasonal variability of the spatial footprints in the three regions.