At least 46 people have died due to severe flooding in western Europe, caused by what experts described as the heaviest rainfall in a century.

Up to 70 people are missing in Germany after flash floods swept across western and southern parts of the country, causing buildings to collapse, police said Thursday. Germany is worst hit with 40 people killed, while six people died in Belgium. Luxembourg and the Netherlands are also affected.

“In some areas we have not seen this much rainfall in 100 years,” Andreas Friedrich, a German weather service (DWD) spokesman, told CNN. He added that “in some areas we’ve seen more than double the amount of rainfall which has caused flooding and unfortunately some building structures to collapse.”

The German regions of North-Rhine Westphalia, Rhineland-Palatinate, and Saarland were worst affected, Friedrich added.

German Chancellor Angela Merkel’s spokesman offered her condolences to the families of the victims. ”I am shocked by the disaster that so many people in the flood areas have to endure. My sympathies go out to the families of the dead and missing,” Steffen Seibert wrote on Twitter.

Merkel is currently in Washington DC to meet President Joe Biden Thursday during what is likely her last visit to the US before stepping down as Chancellor in the fall after 16 years in power.

Armin Laschet, the premier of North Rhine-Westphalia and the Conservatives’ candidate to succeed Merkel, visited North-Rhine Westphalia on Thursday.

“We will be faced with such events over and over, and that means we need to speed up climate protection measures, on European, federal and global levels, because climate change isn’t confined to one state,” Laschett said.

In neighboring Belgium, at least six people died in floods in the southern region of Wallonia, CNN affiliate RTBF reported Thursday, citing the magistrate on duty at the Verviers prosecutor’s office and the governor of the Liège province.

The Wallonia region borders North-Rhine Westphalia. The floods have also disrupted Belgium’s national railway network, Infrabel, stopping services in the French-speaking south of the country, the company said Thursday in a press release.

France has offered to send 40 firefighters to Belgium, the French interior minister Gérald Darmanin tweeted on Thursday.

And the European Union activated the civil emergency response mechanism to help areas of Belgium affected by floods, the EU Commission said Thursday in a statement.

“Belgium, Luxembourg, Netherlands, Germany you can count on the EU’s help to face these dramatic floods. My thoughts are with the victims of these tragic events and with all who will have to rebuild what they have lost. I want to thank all rescue teams for their invaluable help and relentless efforts,” EU Council president Charles Michel tweeted Thursday.

Shipping was also suspended on the River Rhine, one of Germany’s longest and most important arteries of industrial transport, according to NTV news.

DWD spokesman Friedrich said the downpours were caused by cooler and warmer rainfall mixing. “It came from France at the beginning of the week to Germany and has been sitting over Germany for the last 48 hours,” he said.

”For now we predict the worst of the torrential rainfall is over, though more heavy rain is due in southwestern Germany on the upper reaches of the Rhine, [Thursday] and Friday,” he added.