Large scale european flooding under climate change

The devastating floods in 2002 brought damage to large parts of the Elbe catchment. While large floods are repeatedly affecting the central European river catchments, the extreme severity and problems in handling these events have brought them to the attention of the public. Concerns have been raised that climate change could lead to more and even stronger flooding events in the future.
Prof. Uwe Ulbrich, leading meteorologist at the Institut für Meteorologie of Freie Universität Berlin, is addressing the economic risks of flooding in large river basins under current climate conditions by uniquely combining meteorological and hydrological approaches. In collaboration with Prof. Bruno Merz, leading hydrologist from GeoForschungsZentrum Postdam, he is developing a methodology for the Elbe river basin, which takes into account the complete flood risk chain from the flood-triggering weather event, to runoff* generation in watersheds, to flood routing in rivers and finally to flood damage.
Their approach starts from the identification and classification of the hydrological and meteorological pre-conditions leading to flood situations in the Elbe river basin. From a hydrological perspective, around 50 % of flood situations are preceded by high soil moisture content throughout the whole catchment. On the other hand, there are also floods resulting from high soil moisture restricted to the highlands or the upstream part of the catchment. For the meteorological conditions leading to summer flooding, the main pattern preceding the events shows a cyclone over Southern Europe, which transports moist air from the Mediterranean towards central Europe, typical for the so-called “Vb – situations”. During winter, the patterns mostly show a strong zonal flow, carrying moist air from the North East Atlantic.
In a subsequent step, this pattern analysis will serve as the basis for estimating joint probabilities of the occurrence of hydro-meteorological pattern combinations that are flood prone and assess damage associated to basin runoff, opening new opportunities for flood-risk management.