Multi-day extreme precipitation caused major floods in India during summer monsoon of 2024

Abstract

The risk of extreme precipitation and flooding has increased in India due to climate change. During the 2024 summer monsoon season, three major extreme precipitation events occurred across the western, southern, and northern states of India, leading to widespread flooding in these regions. We examine the causes and impacts of extreme precipitation and flood events using a combination of observational data, reanalysis data sets, and hydrological models. In all the three regions, extreme rainfall occurred immediately after multiday continuous precipitation, resulting in catastrophic flooding. The 3-day extreme precipitation that caused flooding in the three regions had return periods of more than 75 years, 100 years, and 200 years, respectively. The primary moisture sources for the Gujarat floods were the Arabian Sea and the Indian Ocean, while the floods in Andhra Pradesh and Telangana were mainly sourced by the Bay of Bengal. For the floods in northern India, the dominant moisture sources were recycled land moisture and moisture transport from the Bay of Bengal. These moisture inflows, coupled with favorable atmospheric conditions, resulted in multiday extreme precipitation in the three regions. Saturated soil moisture conditions before the extreme precipitation contributed to high runoff, triggering extensive flooding in all the three regions. Our findings highlight the growing challenge of managing such extreme events as their frequency and intensity are projected to increase under a warming climate.