Most floods are predictable

Germany, the Netherlands, Belgium and Luxembourg were hit by catastrophic floods in the summer of 2021. Water levels rose to historic levels and many houses collapsed and were swept away by strong currents. Almost 200 people died.

In retrospect, inadequate flood prevention measures and lack of preparedness were identified.

Berit Arheimer is a professor of hydrology at SMHI and co-author of the new study. Natural Earth Sciences. The research team compiled data from 8,000 gauge stations around Europe between the years 1810 and 2021. A total of 510 extra-heavy floods were identified, and 95.5 percent of the observed floods could be predicted, the researchers say. Based on previous events in similar locations.

Researchers now hope municipalities and regions can better prepare by looking at cautionary examples from other countries.

– This torrent will end up everywhere! It is not certain where they end up before, but similar phenomena occur in areas with similar climates and similar natural geography. It’s important to zoom in properly, and not just look at the specific water you’re interested in, says Berit Arheimer.

Researchers divide Europe into five major hydrological regions with similar water levels. By comparing your municipality to places in other countries with similar weather, rocks, land use, topography, soil type and number of lakes, you can learn a lot, says Berit Arheimer.

According to the model, northern parts of Sweden have similar conditions to Finland, northern Norway and northern Russia. The west coast should watch out for severe flooding in Iceland and the UK. Eastern Sweden should compare itself to Lithuania and Poland.

If Gothenburg City Council were to develop a new flood plan, could it look at extreme flood events in Great Britain and plan accordingly?

– Yes! They should not compare themselves to Norrkoping, but look west, says Berit Arheimer.

Overall, he thinks Swedish municipalities have become more prepared for floods in recent years. Even among individuals, she thinks she’s seeing increased awareness.

– I usually insist on planning for high runs following the warnings, even though it never happens. Clean out the basement occasionally and store photos in the attic instead of the basement. Get non-return valves and good insurance!