European Floods: Comments From Moody’s

It’s been a brutal week or so across much of central and Eastern Europe as regards wet weather. Here are some comments by Steffi Uhlemann-Elmer, Director, Product Management, Moody’s;

The ongoing flooding in Central and Eastern Europe calls into memory some of the most destructive, widespread, and costliest flood events affecting this region. These events in 2013, 2002, 1997, and 1954 are all known to have been associated with a so-called Vb (Five-B) weather pattern. Economic losses of each event have, if trended to today’s values surpassed the €10 billion mark with the 2002 event reaching a total of €37 billion. (Data source: EEA, trended to 2022 values).

This record was only recently broken by the deadly flood events in central Europe in 2021, another summer flood event, which reached well above €40 billion in economic loss.

The current event follows the typical Vb track; a low-pressure system that typically evolves south of the Alps, and slowly moves on a track further east and northwards. The system moves counterclockwise in a wide arc and circulates warm and very moist air from the Mediterranean to the north where it meets cooler air masses on a trajectory south and additionally gets pressed against the mountain ranges in its way. This results in persistent and widespread heavy precipitation in the river basins of the Odra, Elbe, and Danube with many violent flash floods in their mountainous tributaries and headwater catchments.

With the weather pattern having been forecast for over a week, warning chains had been activated, and preventive measures such as the release of water from dams and catastrophe response plans to coordinate efforts across states, regions, and communities have been activated.

These measures will make a substantial difference in the loss outcome compared to the 1997 and 2002 events in particular. However, remote and mountainous regions are going to suffer the most, and many areas have already reported major damage from the ongoing event. Further, the ability of flood defenses to withstand the flood wave as it propagates down the major rivers, the final height of the flood peak, and its duration are major determinants of the total cost.

Rainfall totals of more than 100 millimeters per day have been widely observed, with over 300 millimeters in three days for locations in the Czech Republic and Austria. The Lower Austria Province (pop. ~1.7 million) in northeast Austria, has been declared a catastrophe zone, with more than 1,000 houses have been evacuated in Lower Austria, with three fatalities.

In Czechia, 260,000 households have been affected by power outages, and more than 12,000 people have been evacuated across the country. Over the next few days, the area of low pressure is expected to move slowly south towards the Mediterranean Sea, which is forecast to bring additional rainfall to Italy, Croatia, and Greece, while rainfall is expected to gradually ease in the previously impacted areas.

Flooding is expected to continue for the rest of this week, with flood warnings across Czechia and Germany.