Tropical cyclone storm surge probabilities for the east coast of the United States: A cyclone-based perspective

Abstract. To improve our understanding of the influence of tropical cyclones (TCs) on coastal flooding, the relationships between storm surge and TC characteristics are analyzed for the east coast of the United States. Using observational data, the statistical dependencies of storm surge on TCs are examined for these characteristics: distance from TC center, TC intensity, track path angle, and propagation speed. Statistically significant but weak linear correlations are found for nearly all sites. At each location, storm surge is influenced differently by these characteristics, with some locations more strongly influenced by TC intensity and others by the distance from the TC center. The correlation for individual and combined TC characteristics increases when conditional sorting is applied to isolate strong TCs close to a location, though the fraction of surge variance explained is never greater than 60 %. The probabilities of TCs generating surge exceeding specific return levels (RLs) are then analyzed for TCs that pass within 500 km of a location, where between 7 % and 26 % of TCs were found to cause surge exceeding the 0.5-yr RL. If only the closest and strongest TCs are considered, the percentage of TCs that generate surge exceeding the 0.5-yr RL is between 30 % and 50 % at sites north of Sewell’s Point, VA, and over 70 % at almost all sites south of Charleston, SC. Overall, this analysis demonstrates that no single TC characteristic dictates how much surge will be generated and offers a unique perspective on surge probabilities that is based on all TCs rather than focusing only on those that cause extreme surge.