Flooding in the Ahr Valley

A storm depression causes immense devastation in western Germany

Chronicles report some 70 severe floods in the Ahr Valley over the last 500 years, with one especially destructive flood occurring every century. 64 people died in the flood of 1804 and 57 lost their lives in the high waters registered in this area in 1910. The regional government drew up plans in the 1920s to build flood defences, but they were delayed by the expansion of the nearby Nürburgring race track and were then never built. The area around the left tributary of the Rhine receives relatively little rainfall, and the Ahr is usually a shallow river with a depth of well under one metre. However, the valleys in the area are narrow and deep in places, and their slate substrate is impermeable to water. Heavy and prolonged rainfall can cause water levels to rise rapidly, especially in the upper reaches of the watercourse.

The first warnings of serious flooding in the Rhine region caused by Storm Bernd came in from the European Flood Awareness System on 10 July 2021. 14 July saw the German Weather Service forecast extreme storms in western Germany and told the relevant federal states to expect flooding. For its part, the Rhineland-Palatinate State Environment Agency issued its highest warning level, whilst the district administration responsible for the Ahr Valley set up a crisis team. Despite this level of preparation and awareness, the impending disaster was recognized late and a disaster alert was not issued until shortly before midnight on 14 July 2021. That night, more rain fell in 24 hours than over the whole of July, causing water levels in the River Ahr to rise to between seven and ten metres – the highest since records began. The river burst its banks and caused widespread flooding. The full extent of the disaster became apparent in the morning: over 9,000 buildings and 100 bridges were destroyed or severely damaged and 135 people had died. A further 50 deaths brought the grim total to 185 lost lives, making this one of the worst natural disasters in German history.