European floods of July 2021 (Bernd)

The July 2021 European floods were caused by the Bernd low, which sat almost still and dumped extreme rainfall on western Germany, eastern Belgium, Dutch Limburg and Luxembourg from July 12 to 15, 2021. Overnight on the 14th, the Ahr swept away the villages in its valley in Rhineland-Palatinate. In Belgium the Vesdre wrecked Verviers and Pepinster. The death toll passed 200, more than 180 of them in Germany. The German insurance association (GDV) put German insured losses at over 8 billion euros, its worst natural catastrophe on record, far ahead of the 2002 Elbe flood. The federal government and the Länder set up a 30 billion euro rebuilding fund, because natural hazards cover (Elementarschadenversicherung) is optional and fewer than half of homes carried it. In Belgium the law caps each insurer's commitment per natural catastrophe; the Walloon region negotiated with the industry to go past that cap and picked up the rest itself. For modelers, the lesson came from small catchments. Narrow, poorly gauged rivers where flood models calibrated on large rivers saw almost nothing. The Ahr's historical floods sat in the archives, not in the catalogs. On the reinsurance side, everything turned on the hours clause: does rain spread over several days and several countries make one event under the treaty, or several? The answer depends on each contract's wording, and it weighed heavily on per-event excess of loss covers and on reinstatements. In Germany, the idea of compulsory natural hazards insurance has come back into political debate every year since.