At least 43 people have died in western Germany and many more are missing following severe floods, police say.
The worst of the flooding has been in the states of Rhineland-Palatinate and North Rhine-Westphalia, where buildings and cars have been washed away.
At least six others have died in neighbouring Belgium, and the city of Liège has urged all residents to leave.
It follows record rainfall in parts of western Europe that have caused major rivers to burst their banks.
The Netherlands has also been badly hit, with flooding rivers damaging many houses in the southern province of Limburg. A number of care homes have also been evacuated.
German Chancellor Angela Merkel, who is in the US ahead of a meeting with President Joe Biden, said she was “grieving those who have lost their lives” in the flooding.
“My thoughts are with you, and you can trust that all forces of our government – federal, regional and community – collectively will do everything under the most difficult conditions to save lives, alleviate dangers and relieve distress.”
Malu Dreyer, chief of Germany’s Rhineland-Palatinate state, described the flooding as a “catastrophe”.
“There are dead, missing and many people still in danger,” she said. “All of our emergency services are in action round the clock and risking their own lives.”
At least 19 people died in the Ahrweiler district of Rhineland-Palatinate, after the Ahr river, which flows into the Rhine, burst its banks.
Police helicopters and hundreds of soldiers have been deployed to some areas to help stranded residents. Earlier, police said dozens of people were waiting on rooftops to be rescued.
Schools have been closed around the west of the country, while transport links have been severely disrupted.