At least two people have died and at least 25 are missing after a powerful storm hit southern France and north-western Italy.
Named Alex, it brought fierce winds and torrential rains causing severe floods, reports BBC.
A number of villages suffered serious damage around the southern city of Nice. Its mayor described it as the worst flooding in living memory.
In northern Italy, roads and bridges were swept away by floodwater, while several rivers overflowed their banks.
One of the victims in Italy was a firefighter in the Aosta Valley, while the other was a man in his 30s whose car was swept into a river in the Piedmont region.
Another 17 people are said to be missing in the country's north-west after heavy rains hit overnight; among them is a group of at least four German trekkers who did not return from a trip in the mountains, officials said.
In Piedmont, several villages were cut off after the rains made roads impassable. The situation there was described as "extremely critical" by officials.
Hundreds of aid workers have been sent to help rescue efforts in the cut-off villages.
The storm also affected the north-western regions of Lombardy and Liguria.
The city of Venice, which had been braced for high waters after suffering violent storms in August, was successfully protected by a flood barrier system recently declared fully operational.
In France, eight people are said to be missing.
Several villages north of Nice, located in steep-sided valleys, have been cut off.
After flying over the worst-hit area by helicopter, Nice Mayor Chistian Estrosi told French news channel BFM: "The roads and about 100 houses were swept away or partially destroyed."
Meteorological agency Météo-France said 450mm (17.7in) worth of rain fell in some areas over 24 hours - the equivalent of nearly four months of rain at this time of year, reports Reuters news agency.
The Alpes-Maritimes department was placed on red alert on Friday, but the alert level has now been downgraded to orange as the storm moves towards Italy.
Beaches in Nice and other coastal cities were closed, and people were asked to stay at home, the AFP news agency reports.
On Friday, the storm buffeted France's western Atlantic coast, causing tens of thousands of homes to lose power.
Winds of more than 180km/h (112mph) were recorded in Brittany on Thursday and Friday.