Analysis of flood fatalities in July 2021: lessons for European flood risk management

In July 2021, extraordinary flooding claimed more than 220 lives in Germany and Belgium, an unprecedented number in recent decades in both countries. To better understand underlying causes, the individual circumstances of 224 fatalities were analyzed based on documents and interviews. Intersections with hazard maps indicate that 58% of the fatal incidents occurred outside officially mapped flood hazard zones. In addition, fatal pathways revealed deficiencies in warning, evacuation and behavior. Around two thirds of the people who died indoors were caught by surprise in souterrain apartments or on the ground and upper floors of their homes, suggesting that these buildings should have been evacuated in time. 22% died in basements mostly while mitigating damage, checking pumps or starting cleanup, pointing towards deficiencies in communicating safe behavior during flooding. The circumstances of outdoor deaths are often less clear, but underline the risks of being outdoors during a flood, even in places that are usually safe to cross a river such as bridges. Despite regional differences between the Walloon Region (Belgium), North Rhine-Westphalia and Rhineland-Palatinate (both Germany), it is generally recommended to clearly communicate appropriate behaviors in warning messages. Evacuation needs to take place in areas where moderate to high water levels are expected, particularly where basement or ground level apartments are expected to be flooded. Special attention should be paid to the safety of elderly people, who are significantly overrepresented among the fatalities of 2021. Finally, the European Floods Directive and its implementation need to better address worst-case scenarios in hazard mapping and risk communication.