Preface: Advances in pluvial and fluvial flood forecasting and assessment and flood risk management

The special issue "Advances in pluvial and fluvial flood forecasting and assessment and flood risk management" builds on topics covered in the session "Advances in pluvial and fluvial flood forecasting and assessment and flood risk management" organized since 2018 at the European Geosciences Union (EGU) General Assembly held in Vienna, Austria.It gathers five research papers on flood modelling and management.Worldwide, flooding is the foremost natural hazard.It affects human life and property, directly and indirectly (e.g.IPCC, 2022;Prieto et al., 2020; Blöschl et al., 2019a; Phillips et al., 2018; Berghuijs et al., 2017; European Parliament, 2017).In the European Union and in the United Kingdom, river flooding causes annual losses of about EUR 7.6 billion and affects around 160 000 people per year (European Commission, 2023).Dottori et al. (2023) state that under a 3 °C temperature increase scenario and without adaptation, annual flood losses in Europe would rise to EUR 44 million, affecting 0.5 million of Europeans every year until the end of the century.Flooding and severe storms are among the most recurrent weather and climate disasters in the United States, causing USD 492 billion in economic damages in the past 30 years (NOAA, 2024).In developing or least developed economies, 28 million people are prone to coastal flooding due to tropical storms (Edmonds et al., 2020).Additionally, in these countries, especially in the tropics, long-term climatic fluctuations such as ENSO (El Niño-Southern Oscillation) can lead to extreme sea level events and related coastal hazards (Pelckmans et al., 2023).Developed countries are expected to benefit from the most advanced mitigation measurements.Nonetheless, the costliest flood event over the last decade occurred in July 2021 in Germany and Belgium, with losses of EUR 44 billion (European Environmental Agency, 2023), showcasing that the whole world needs to adapt to offset the projected rise in flood risk.In 2022, floods caused the death of roughly 7400 people globally, and more than 54 million people were impacted by floods worldwide in 2022 (Burgueno, 2023).Global warming will also slow down atmospheric dynamics, resulting in more precipitation falling over a longer period, thus increasing flooding hazard (Kossin, 2018; IPCC, 2023).Despite the many hydrological and hydrodynamic modelling techniques currently available to inform flood risk assessment and management (Prieto et al., 2021; 2022; Han, 2011; Mignot and Dewals, 2022), many open questions remain, as reflected for instance in the list of "Twenty-three Unsolved Problems in Hydrology" (Blöschl et al., 2019b) and in the programme of the HELPING decade of the International Association of Hydrological Sciences (IAHS).Two particularly timely challenges in flood risk management relate to (1) improvement of spatial predictions of urban flooding and the quantification of their uncertainties (Skougaard Kaspersen et al., 2017; Hooker et al., 2023) and (2) evaluation of the effectiveness and efficiency of non- Published by Copernicus