A massive "water bomb" led to the death of 10 people as 16 inches of rain fell in just two hours in Italy.
Three others are missing after the subsequent flash floods.
The incident in the central Italian region of Marche occurred on Thursday night affecting the streets of towns in the provinces of Pesaro-Urbino and Ancona.
Cars were swept away as the rain left a trail of debris and mud on Italian streets, where a cleanup operation involving locals is now underway.
One of the people reported as missing was a young child travelling in a car. Reports say his mother was rescued but the child was washed away as people took refuge on the roofs of houses.
Rescue workers had to use dinghies to bring people to safety.
Ludovico Caverni, the mayor of Serra Sant'Abbondio, told RAI the rain and flood was "like an Earthquake" as forecasters revealed the weather was far more extreme than it was expected to be.
Civil protection head in Marche, Stefano Aguzzi, said: "We were given a normal alert for rain, but nobody had expected anything like this.
Italy is currently facing the run-up to general elections and parties announced the suspension of campaigning in the Marche region.
Cente-left Democratic Party candidate Enrico Letta said: "Stunned and speechless in the face of the tragedy that struck Marche.
"Thinking (of) and crying for the victims."
Letta has previously spoken of climate change and has blasted frontrunner Giorgia Meloni by arguing: "How can you think that the fight against climate change is not the first priority?"
Meloni, of the far-right Brothers of Italy Party, said she had "full solidarity" with the victims.
The country has been suffering from its worst drought in decades, making flooding more likely to occur as the ground is too dry to absorb the sudden on rush of water quickly enough.
The country's largest lake, Lake Garda dropped near to the lowest level ever recorded while the Po river levels were so low that World War 2 artefacts were revealed for the first time in years.
A barge sunk during the conflict appeared, as did an unexploded bomb found by a fisherman.
The safely detonate the bomb, police had to clear away 3,000 people living nearby while the surrounding airspace had to be closed.
In June, Prime Minister Mario Draghi said: "There are two categories of causes for this water crisis: One is the rainfall deficit of the last three years. There has been a low level of rainfall, of course not just this year but also in previous years.
"The general rise in temperatures is also contributing; there is no doubt that climate change is having an effect."
