The death toll from heavy flooding in western Germany rose to 81 on Friday and more than 1,000 residents are believed to be missing in one of the country’s most destructive natural disasters in years.

Officials in the Ahrweiler district, south of Cologne, said about 1,300 people appeared to be missing as of Thursday night. Cellular networks are down, however, making it hard to account for the missing.

“Due to the complex damage situation, a final assessment of the situation is not yet possible,” the district government wrote on its website.

Torrential rains on Thursday caused waters from overflowing rivers to wash through many districts of Germany’s North Rhine-Westphalia and Rhineland-Palatinate regions. Transport networks were blocked in some areas, while houses collapsed in the district of Erfstadt, outside Cologne.

Germany’s interior minister Horst Seehofer told the newspaper Spiegel that the government would seek to offer financial support to hard hit districts as soon as possible.

“In my entire political career in Germany I have never seen a flood with such terrible consequences, with so many dead and missing,” Seehofer said. “Nobody can seriously doubt that this catastrophe is related to climate change.”