Multivariate compound events drive historical floods and associated losses along the U.S. East and Gulf coasts

This study presents an impact-based analysis of compound flooding across 203 coastal counties along the U.S. Gulf and East coasts by integrating data from multiple flood drivers with socio-economic loss records from 1980 to 2018. 

The findings indicate that approximately 80% of all recorded flood events in the study area were compound rather than univariate. Additionally, historical compound flooding events in most counties were driven by more than two flood drivers (hydrological, meteorological, and/or oceanographic), with distinct spatial clusters exhibiting variability in the dominant drivers of compound flood events. Moreover, the study reveals that in more than 80% of the counties, over 80% of recorded property and crop losses were associated with compound flooding. Nearly 80% of counties experienced higher median losses from compound events than from univariate ones. For these counties, median property losses were over 26 times greater, while median crop losses were more than 76 times higher for compound events on average. By addressing some of the limitations of previous studies that relied on pre-defined flood drivers, this analysis provides new insights into the complex relationships between hazards and their socio-economic impacts.