Complex networks reveal teleconnections across cascading floods in the Yangtze River Basin

Floods, driven by a sequence of hydroclimatic processes, can propagate across multiple domains—from precipitation to water yield and streamflow—resulting in cascading effects. However, the teleconnection patterns and synchronization characteristics of such cascading floods, shaped by the sequential accumulation and redistribution of water, remain poorly understood. To address this gap, we apply complex network analysis to investigate flood propagation and synchronization dynamics across 125 subbasins in the Yangtze River Basin (YRB) from 1961 to 2020. By integrating three hydrological variables—precipitation (P), water yield (Y), and streamflow (S)—we construct six flood-related networks, revealing key differences in connectivity and propagation characteristics. Our findings show that streamflow-related networks (P–S, Y–S, and S–S) exhibit stronger connectivity, characterized by more links, greater stream order differences, longer total propagation distances, fewer isolated subbasins, and larger cluster sizes, compared to precipitation- and water yield-related networks. Precipitation-related networks (P–P, P–Y, and P–S), in contrast, reflect the influence of large-scale atmospheric processes, as indicated by the longer individual links. Meanwhile, the water yield-dominated network (Y–Y) has the fewest links, likely due to local factors that constrain propagation. A significant large-scale propagation mechanism, where downstream water yield regulates upstream precipitation in the YRB is identified, highlighting the potential role of hydrological feedbacks in shaping flood dynamics. In addition, spatial patterns of cascading floods underscore the critical role of certain subbasins as both flood propagators and hubs, offering information for flood management strategies at both local and regional scales. This study presents a novel framework for understanding cascading floods in complex hydroclimatic systems and underscores the need for further research into teleconnection-driven extreme events.