Adding to the devastation, several more were feared dead in a landslide in northern Germany triggered by floods. Hundreds were unaccounted for in the country, while in Belgium more than 21,000 people left without electricity in one region.
Death toll from heavy rains and floods lashing western Europe has risen to least 103 in Germany, bringing the total number of deaths in Europe to 118, with many more people missing after rising waters caused several houses to collapse.
"We are mourning 60 dead at the moment," Rhineland-Palatinate premier Malu Dreyer said on Friday, up from the previous total of 50 in the German state.
The country is experiencing one of the worst weather disasters since World War II, desperate residents sought refuge on the roofs of their homes as rescue helicopters circled above.
In the devastated Ahrweiler district of Rhineland-Palatinate around 1,300 people were unaccounted for, although local authorities told Bild the high number was likely down to damaged phone networks.
Regional interior minister Roger Lewentz told broadcaster SWR that "we believe there are still 40, 50 or 60 people missing, and when you haven't heard for people for such a long time...you have to fear the worst."
"The number of victims will likely keep rising in the coming days," he added.
Unusually heavy rains also inundated neighbouring Luxembourg, the Netherlands and Belgium.
On a visit to Washington, German Chancellor Angela Merkel said her "heart goes out" to the victims of the flooding.
"I fear that we will only see the full extent of the disaster in the coming days," she said, adding that the government is doing its "utmost to help (people) in their distress".
NEW 🚨 About 60 dead, dozens missing, thousands out of power after devastating floods in Germany— Insider Paper (@TheInsiderPaper) July 15, 2021
US President Joe Biden, speaking alongside Merkel at a joint news conference, offered his "sincere condolences and the condolences of the American people for the devastating loss of life and destruction".
Around 1,000 soldiers have been deployed to help with rescue operations and rubble-clearing in affected towns and villages.
Streets and houses under water, overturned cars and uprooted trees could be seen everywhere the floodwaters had passed, while some districts were cut off from the outside world.
Around 15,000 members of the German emergency services, police and army were on the ground in the worst-hit areas.
North Rhine-Westphalia (NRW) premier Armin Laschet, who is running to succeed Merkel in September elections, cancelled a party meeting in Bavaria to survey the damage in his state, Germany's most populous.
"We will stand by the towns and people who've been affected," Laschet, clad in rubber boots, told reporters in the town of Hagen.
He called for "speeding up" global efforts to fight climate change, underlining the link between global warming and extreme weather.
Because a warmer atmosphere holds more water, climate change increases the risk and intensity of flooding from extreme rainfall.
This drone footage shows the extent of damage caused by record rainfall in areas of Belgium and Germany. The torrential rain has caused river banks to burst and flood entire neighborhoods of certain cities. At least 42 people have died in Germany and dozens are still missing. pic.twitter.com/PXu8Xee1ay— NowThis (@nowthisnews) July 16, 2021
Wuppertal Dam in Germany has breached. Watch the water … 🐇 pic.twitter.com/APxwP1i4ah— Lee (@VictoryDay_Hope) July 15, 2021
Meanwhile, Belgium has also seen several days of heavy rain that has caused rivers in the French-speaking region of Wallonia to burst their banks. Four were reported dead.
The provinces of Liege and Namur were especially affected, with the resort town of Spa completely flooded.
Residents in Liege were told Thursday to urgently evacuate neighbourhoods near the banks of the Meuse river.
In the town of Chaudfontaine, daily Le Soir reported that nearly 1,800 people had to evacuate.
The country's Infrabel rail network said it was suspending services in the southern half of the country, given the risks to travel.
Dutch safety workers have also evacuated hundreds of homes in the southern town of Roermond in Limburg province.
The Meuse in Limburg was expected break its banks early on Friday, and to reach its highest level in 200 years, the ANP news agency reported.
Thousands of people were being urged to evacuate their homes, especially in provincial capital Maastricht.
Several municipalities in Limburg have already declared a state of emergency making evacuation compulsory.
The Luxembourg government set up a crisis cell to respond to emergencies triggered by heavy rains overnight as Prime Minister Xavier Bettel reported "several homes" had been flooded and were "no longer inhabitable".