Seasonal Drivers of Storm Tides and Coastal Flood Impacts Along the US Atlantic Coast
Abstract
Due to sea‐level rise, densely populated coastal areas are facing increasing flood risk during coastal storms. Much of the US East Coast experiences extratropical cyclones (ETCs) more frequently than tropical cyclones (TCs), yet many studies on extreme flood risk focus primarily on TCs or exclude ETCs altogether. ETCs occur primarily during November to April (henceforth, the cool season), while TCs occur primarily during May to October (henceforth, the warm season). This study performs a quasi‐nonstationary skew surge joint probability (qn‐SSJPM) analysis of storm tide exceedance distributions for cool and warm seasons from 23 tide gauges along the US East Coast to assess seasonal contributions to extreme sea levels. From Boston, MA northward, cool‐season extreme storm tides predominate, while south of Wilmington, NC, warm‐season storm tides predominate. Using an illustrative property damage curve, we show that, for New York City, cool‐ and warm‐season storms cause comparable amounts of average annual property damage. These findings highlight the importance of treating cool‐ and warm‐season storms as statistically separate to improve flood risk analysis.
Plain Language Summary
Coastal communities face a growing risk of flooding as sea levels rise and storm characteristics change. On the US East Coast, both cool‐season storms (e.g., nor’easters) and warm‐season storms (e.g., hurricanes) can cause damaging flooding. For example, at The Battery, 88 out of the 100 largest extreme water levels were caused by nor’easters, rather than hurricanes. However, past research on the effects of climate change on flood risk has often focused more on hurricanes than nor’easters. This study examines how storms in different seasons contribute to extreme sea levels at tide gauges along the coast. We find that north of Boston, MA, the most extreme flooding occurs in the cool season, while south of Wilmington, NC, the most extreme flooding occurs in the warm season. In the mid‐Atlantic region, both seasons contribute significantly to flood events. At all locations, cool‐season storms drive the more routine extreme sea levels. These findings highlight the importance of studying winter storms to improve coastal flood preparedness.
Citation
Apoznanski, D. K., Baranes, H. E., Kopp, R. E., & Broccoli, A. J. (2026). Seasonal drivers of storm tides and coastal flood impacts along the US Atlantic Coast. Earth’s Future, 14, e2025EF007304. https://doi.org/10.1029/2025EF007304