The conterminous United States are projected to become more prone to flash floods in a high-end emissions scenario
Zhi Li, Shang Gao, Mengye Chen, Jonathan J. Gourley, Changhai Liu, Andreas F. Prein, Yang Hong
Abstract
Abstract Flash floods are largely driven by high rainfall rates in convective storms that are projected to increase in frequency and intensity in a warmer climate in the future. However, quantifying the changes in future flood flashiness is challenging due to the lack of high-resolution climate simulations. Here we use outputs from a continental convective-permitting numerical weather model at 4-km and hourly resolution and force a numerical hydrologic model at a continental scale to depict such change. As results indicate, US floods are becoming 7.9% flashier by the end of the century assuming a high-emissions scenario. The Southwest (+10.5%) has the greatest increase in flashiness among historical flash flood hot spots, and the central US (+8.6%) is emerging as a new flash flood hot spot. Additionally, future flash flood-prone frontiers are advancing northwards. This study calls on implementing climate-resilient mitigation measures for emerging flash flood hot spots.