Three houses and part of a 19th-century castle collapsed in surging waters on Friday in the German town of Erftstadt-Blessem, southwest of Cologne, where the swollen Erft River inundated the city, setting off a landslide.
The regional authorities said that people who had returned to check on their homes despite warnings were stranded in the town and had to be rescued by boat.
“We keep getting calls from people who ignored the warnings and went back to their homes in the endangered area, or never left them,” said Dirk Schneemann, a spokesman for the Cologne regional district. “Many people are still in their homes. We are not able to reach all of them.”
The local hospital and several nursing homes had to be evacuated, electricity was still cut off and cellphone service was spotty, he said. Many people were missing.
“We expect there to be many dead, but we do not know,” said Herbert Reul, the interior minister of North Rhine-Westphalia State, which includes Erftstadt-Blessem.
Spinghar Safi fled the town with his family on Thursday after the fire brigade warned that the rising waters could threaten his home. He said that lower-lying homes several feet below his house had already flooded by the time he left.
“Many homes are underwater, and many others have collapsed,” he said in a telephone interview from a cousin’s home in a nearby town where he and his family were taking shelter.
They first gathered at a central location where firefighters and rescue workers said they would collect people, but after waiting for about four hours, Mr. Safi, an Afghan who came to Germany as a refugee, decided to wade through calf-deep water out of the town to reach his cousin’s home on foot.
“I have lived in Erftstadt for 15 years, and I have never seen such a thing in my life,” he said. “Not in Afghanistan and not here.”