Three people are missing after floodwaters swept through the south-eastern Swiss town of Misox in the alpine valley of Graubünden.
A massive thunderstorm on Friday night caused rivers to break their banks, flooding streets and causing several dozen residents to be evacuated from their homes, local authorities said.
Further west, the alpine resort of Zermatt has been isolated by floodwaters.
Footage from the town, which lies at the base of the iconic Matterhorn mountain, showed floodwaters raging through the streets on Friday.
Train services between Visp and Zermatt have been suspended, and the road between Täsch and Zermatt has been closed, leaving the resort completely inaccessible.
Authorities had prepared for some overflow, restricting public access to the banks of the Rhône and its off-shoot rivers from Friday.
The Graubünden government said it was following the situation with "great concern" and issued thanks to the local emergency services.
