The floods in Germany and Belgium, unexpectedly for many, led to serious destruction and a large number of victims.
The number of confirmed victims of the tragedy has already reached 196 people. But dozens more people are still missing, so the death toll could rise.
What exactly led to such victims, now both officials and scientists are trying to understand. Why were wealthy European countries not ready for a natural disaster?
In Germany and Belgium, there are warning systems for the possible threat of natural disasters. They were commissioned after the devastating floods in Europe in 2002. Then 110 people died.
Hydrology professor Hannah Klock was one of the founders of the European Union's early warning program for dangerous floods. She continues to advise the European flood reporting system.
"The system issued a warning: very serious rains and floods are coming, please note. Further, the national authorities had to use this information," the professor said in an interview with the BBC.
According to Klock, people on the ground have interpreted the system's warning differently. Somewhere they took measures, but somewhere people did not even know that extreme bad weather was approaching.
A spokesman for the German Meteorological Service (Deutscher Wetterdienst) said it has issued a number of extreme precipitation warnings. And then, according to the representative of the department, it was the local authorities who had to determine the risk of flooding and take appropriate measures.
According to Professor Klock, there have been disruptions in the decision chain in many areas.
According to experts, the disaster prevention system in Germany is rather fragmented. In different federal states (regions of the country), it includes different authorities, which ultimately use different protocols.
At the international level, coordination of efforts is even more difficult. The existing structures for forecasting and preventing floods in European countries differ from each other and do not always interact.
Enlightenment and shovels
Piles of rubbish after flooding in the German town of Bad Neuenahr-Ahrweiler
"I was completely surprised. I assumed, yes, one day water would come here. But not like that! I did not expect anything like this," Michael Arend told Reuters, while wielding a shovel.
He, like other residents of the Ahrweiler district in Germany, took up the large shovels used to shovel snow in order to carry mountains of silt and mud out of their homes after the water receded.
Experts note that many Europeans simply do not realize how dangerous floods and other natural disasters can be.
Frederick Otto, deputy director of the Institute for Environmental Change at Oxford University, believes that it is urgent to start a massive campaign of education to explain to people what critical situations can arise during floods and how quickly events can develop.
“The fact that so many soils are pressurized also leads to more serious impacts as the water simply has nowhere to go,” she added. Soil sealing occurs when land is used for housing, roads and other objects or construction work.
Computers can't handle
Another important factor is global climate change, scientists say.
Even the most modern computers, which are now used by meteorologists, hydrologists and other specialists in this field, are still not powerful enough to predict exactly how a disaster might behave, taking into account many existing factors.
"Current climate computers are not powerful enough and this is a concern," says Julia Slingo, a former chief scientist for the UK Meteorological Service.
According to her, in order to learn how to calculate algorithms and build accurate climate models, the joint work of the world's leading scientists is needed.
“If we do not do this, we will continue to underestimate the intensity and frequency of extreme events, as well as their increasingly unprecedented nature,” says Slingo.
According to the expert, the cost of creating such a climate super-computer can amount to hundreds of millions of dollars. But that spending pales in comparison to the money that has to be spent on disaster relief, says Slingo.
Professor Haley Fowler, who studies the effects of climate change at the University of Newcastle, agrees with her colleague's assessment. She notes that global warming is slowing down the jet stream in the atmosphere. And this, in turn, leads to a slowdown in the movement of storms.
"Extreme precipitation will increase, and the most extreme of them will become more frequent," the scientist predicts.
Now in the most affected areas of Germany, the water begins to subside, but in some places due to heavy rains, the flooding continues, taking away more and more lives. At least one person died on Sunday in Bavaria.