At least 59 people were killed on Thursday as a result of the storm in western Germany.
Hundreds of people are still missing in Rhineland-Palatinate.
About 1,300 people are missing in the town of Bad Neuenahr-Ahrweiler, the city council reported Thursday evening.
A spokesman for the city in the state of Rhineland-Palatinate said the mobile phone network had been down and many people were therefore unreachable.
According to energy supplier Eon, about 165,000 people in western Germany were without power on Thursday.
Rainfall and flooding have caused houses to collapse and municipalities to be cut off from the outside world.
Many sought protection from the floods on trees and roofs of houses.
Rescue workers brought people to safety with boats and helicopters.
"We have never experienced such a disaster. It is really debilitating," said Prime Minister Malu Dreyer (SPD).
The Cologne police report that 20 people have died in the region as a result of the storm, 15 of them in the city of Euskirchen.
People have also died in flooded basements and at least two firefighters died during rescue operations.
The Ahrweiler area in Rhineland-Palatinate has also been hit hard.
There, houses were destroyed in the town of Schuld and at least eighteen people died.
In neighboring North Rhine-Westphalia, state prime minister Armin Laschet visited Hagen and Altena, where a 46-year-old firefighter was killed during a rescue operation.
Drone films havoc in Germany after severe flooding
Army supports emergency services
The heavy rainfall also caused flooding in cities such as Cologne, Hagen and Trier.
A hospital in Leverkusen had to be evacuated and cellars in Wuppertal were flooded.
The emergency services are supported by 850 military personnel.
The armed forces have deployed armored vehicles to clear roads blocked by landslides and fallen trees.
Authorities are also flying helicopters to rescue people who have sought refuge on rooftops.
Chancellor Angela Merkel responded from the United States, where she met President Biden and Vice President Harris on Thursday, "shocked" at the disaster.
She said she sympathized with the relatives of the victims and thanked the "tiring" emergency services for their efforts.
Vice Chancellor Olaf Scholz interrupted his vacation because of the flooding.
The high water also causes a lot of nuisance in the Netherlands and Belgium.
The Belgian authorities have so far reported 11 deaths from the extreme weather.
See also: This is the current state of affairs in Limburg, East Belgium and West GermanyKeywords: