The bridge in Visletteo destroyed due to the storm, in Visletto, in the Maggia Valley, southern Switzerland, on Sunday. AP

Three of the victims were killed early on Sunday in a landslide in the remote Maggia valley, in the Italian-speaking Swiss canton of Ticino, police said in a statement.

The three bodies were recovered in the Fontana area of the Maggia valley and they were currently being identified, while another person was missing in the Lavizzara side-arm of the valley, Ticino authorities said.

A bridge downstream of the disaster area in the Maggia valley was submerged, complicating rescue efforts, they added.

One camp site in the valley has been evacuated by helicopter and 300 people at a local soccer tournament would soon also be evacuated by helicopter, police said.

A view of the Navizence river overflowing in the industrial zone in Chippis, Switzerland. AP

In the southwestern Swiss canton of Valais, police said a man was found dead in a hotel in the Alpine town of Saas-Grund. Police said he was likely surprised by flooding as melting snow compounded violent thunderstorms.

They added that another man was missing in another region in the Valais canton.

Rubble from a landslide caused by severe weather in Saas-Grund, Switzerland. AP

Flooding and mudslides also hit a neighbouring area of Italy, where around 200 people had to be evacuated by helicopter on Sunday from their homes in Cogne in the Valle d'Aosta, the region's governor Renzo Testolin said.

Another 120 people were being evacuated from Alpine villages in the neighbouring Piedmont region after torrential rain, Italian news agencies reported, citing local firefighters.

Reuters