Joint Trends in Flood Magnitudes and Spatial Extents Across Europe. Issue 7 (1st April 2020)

• Record Type: Journal Article
• Authors: Kemter, Matthias; Merz, Bruno; Marwan, Norbert; Vorogushyn, Sergiy; Blöschl, Günter
• Is Part Of: Geophysical research letters. Volume 47:Issue 7(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-01
• Subjects: flood -- synchrony -- magnitude -- climate change -- classification -- spatial statistics; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL087464
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The magnitudes of river floods in Europe have been observed to change, but their alignment with changes in the spatial coverage or extent of individual floods has not been clear. We analyze flood magnitudes and extents for 3, 872 hydrometric stations across Europe over the past five decades and classify each flood based on antecedent weather conditions. We find positive correlations between flood magnitudes and extents for 95% of the stations. In central Europe and the British Isles, the association of increasing trends in magnitudes and extents is due to a magnitude‐extent correlation of precipitation and soil moisture along with a shift in the flood generating processes. The alignment of trends in flood magnitudes and extents highlights the increasing importance of transnational flood risk management. Plain Language Summary: If multiple rivers flood at the same time because of large‐scale rainfall, the resulting damage can exceed the capacities of disaster recovery and insurance companies. We find that events with a large spatial coverage or extent tend to be associated with above average magnitudes of the flooding level. During 1960–2010 flood extents increased in central Europe and the British Isles but decreased in Eastern Europe. These trends are caused by changes in flood generation processes due to a changing climate. If these trends persist into the future, the combination of stronger floods and larger extents is likely to increase the flood risk substantially. Key Points: Flood magnitudes and extents are correlated across Europe Both have increased in central Europe and the British Isles but decreased in Eastern Europe These trends are driven by regional changes in flood generation