Projected changes in flooding: a continental U.S. perspective

Our study focuses on the projected changes in annual and seasonal maximum daily runoff (used as a proxy for flooding) across the continental United States based on outputs from eight global climate models (GCMs) from the Sixth Coupled Model Intercomparison Project (CMIP6). Analyses performed at the regional scale indicate that the GCMs are generally able to reproduce the observed changes in runoff extremes, especially at the seasonal scale, with no single model that outperforms the others across the different seasons and regions. Overall, annual maximum daily runoff is projected to increase during the 21st century, especially in large areas of the southeastern United States and Pacific Northwest, and to decrease in the Rocky Mountains and the northern Great Plains. The largest changes in extremes are projected to be in winter and spring, with a more muted signal for summer and fall.