siteur.blogg.se

Manmade changes to ground surfaces increased the speed of above ground drainage and provided less time for the water to reach further down the groundwater table.Rivers and impounded reservoirs were already at very high water levels, which further reduced the retention capacity.In 2016, for example, an area the size of approximately 90 football fields (≈640,000 m2) were used for building construction every day. The ratio of impermeable surface ground (sealing) to open natural ground surface had been continuously increasing up to the time when the heaviest rains began.The ground had been saturated and the retention capacity of large soil volumes had already reached their limits before the heavy rainfalls starting on 12 July. The region of Germany worst impacted had experienced significant rainfalls over the previous three weeks. Soil condition and capacity to drain and hold water is extremely important.That said, other variables must also be taken into consideration. However, it is thought almost certain that the worsening climate crisis caused the devastating rainfall, as it is a simple physical fact that warm air can hold more humidity than colder air. There are several reasons why this flood was so devastating, and many reasons still to be assessed are currently considered as ‘speculative’. Some EUR 2 billion from the fund has been dedicated to public infrastructure, such as railway systems. Within three weeks of the disaster, the German government launched a EUR 30 billion relief fund. If the warnings and especially the speed of the evacuations was conducted well enough, is still to be evaluated.“ However, what we experienced was that many people did not have a chance to return, either because of limited access to their homes or the fact that their homes or workplaces no longer existed. Ottmar Zeizinger, Risk Engineer at If, followed the development of the flooding notes that, “The evacuation of large living areas, hospitals, the elderly, and homes for mentally and physically challenged individuals, began in the early phase of the disaster. In addition, bridges were destroyed, roads and railway tracks were washed away and electric power, water supplies, sewer systems and communication systems were severely impaired. The flooding resulted in at least 184 fatalities in Germany and 38 fatalities in Belgium, with many more people injured. In the beautiful wine valley of the River Ahr, many large buildings, as well as other types of infrastructure, were completely destroyed. Many dams rapidly filled and were subject to overflowing and some dams were at great risk of collapse. The force of the water moved soil and debris like an avalanche through buildings, towns and valleys. The impact of the energy on the ground below resulted in landslides along the flank sides of the hills, and below relatively even surfaces the water impacted the soil structure and resulted in sink holes. The flash floods and river floods turned small creeks into powerful streams reaching up to 8m water height. In other words, this was the most devastating flood to hit Germany in many years. Large areas received downfalls of 150 l/m2/24hr on average over several days.Īll precipitation rates were beyond the 100-year recurrence interval (meaning that a flood of this magnitude had a less than 1% chance of happening within any given year).

Peak rainfalls were measured on the 14–15 July in the range of 87 l/m2/2hr to 240 l/m2/22hr. In this article, we investigate how the flooding developed, the underlaying causes that are currently known, as well as the insurance claims that followed in the aftermath.ĭuring 12–17 July 2021, the low-pressure system “BERND” caused extremely heavy rainfalls in some regions of Germany. The natural disaster in Germany this summer was a once-in-a-hundred-year event. It will become increasingly important to consider the impact of land use, extreme weather, and natural hazards, when assessing regional risks. Preparing for the adverse effect of climate change will require a proactive approach. This article has previously been published in Risk Consulting Magazine, If.