An overnight storm on Thursday caused one of the city’s largest rivers, the Bisagno, to burst its banks and send torrents of flood waters through the streets on Friday.
The gush of water caught city officials by surprise as it sent torrents of muddy water through the streets, destroying store fronts and sweeping aside cars.
The floods also knocked out the city’s electricity and closed public centers for more than half of the day.
The mayor of Genoa, Andrea Doria, said that the city was not warned in time by Arpal, the meteorology agency for the northwestern Liguria region.
“We act on the basis of the Arpal forecasts, which gave no signs of alarm,” Doria said at a news conference, adding, “The alarm only arrived this morning.”
According to emergency services, the body of a 57- year-old man, who had apparently been swept away by flood waters, was recovered.
The floods covered the streets with over a meter of mud and Italian media reported that a train was also derailed by the floods.
Crews clearing the debris left in the floods aftermath reported that they had found vehicles piled on top of each other or sunk into huge holes in the streets.
Italy’s Civil Protection Department has warned of more heavy downpours over the next few days.
In February, torrential rain caused severe flooding in several cities across the country, including the capital Rome and Pisa.