Coastal locations around the United States, particularly along the Atlantic coast, are experiencing recurrent flooding at high tide. Continued sea-level rise (SLR) will exacerbate the issue where present, and many more locations will begin to experience recurrent high-tide flooding (HTF) in the coming decades. Here we use established SLR scenarios and flooding thresholds to demonstrate how the combined effects of SLR and nodal cycle modulations of tidal amplitude lead to acute inflections in projections of future HTF. The mid-2030s, in particular, may see the onset of rapid increases in the frequency of HTF in multiple US coastal regions. We also show how annual cycles and sea-level anomalies lead to extreme seasons or months during which many days of HTF cluster together. Clustering can lead to critical frequencies of HTF occurring during monthly or seasonal periods one to two decades prior to being expected on an annual basis.

美国各地的沿海地区，特别是大西洋沿岸，在涨潮时经常发生洪水。持续的海平面上升 (SLR) 将加剧目前存在的问题，更多地区将在未来几十年开始经历经常性高潮洪水 (HTF)。在这里，我们使用已建立的 SLR 情景和洪水阈值来演示 SLR 和潮汐振幅的节点周期调制的综合影响如何导致未来 HTF 预测的急性拐点。特别是在 2030 年代中期，美国多个沿海地区的 HTF 频率可能会迅速增加。我们还展示了年度周期和海平面异常如何导致极端季节或月份，在这些极端季节或月份中，许多天的 HTF 聚集在一起。