Witnesses described "unthinkable" scenes of heavy flooding in northern Italy as Storm Boris continued its journey across Europe on Thursday.
People were seen climbing on roofs to escape the water as buildings collapsed in Traversara di Bagnacavallo.
The Italian emergency services carried out helicopter rescues after what one eyewitness said was 36 hours of rain.
Storm Boris had earlier swept across Poland, the Czech Republic, Romania and Austria, killing at least 23 people.