Officials said three people died and one was hospitalized in critical condition after a tornado tossed their car into another lane Wednesday, slamming it into another vehicle, the ANSA news agency reported.
Police said the driver of the second vehicle was killed on impact.
Meanwhile, officials said said an employee of the ILVA steel plant in Taranto was missing after a tornado blew a crane on which he was working into the harbor.
City officials Thursday said about 15 families from Statte were forced to sleep in hotels after a twister destroyed their homes, downed trees and damaged the town's bell tower.
In Tuscany, the regional government declared a state of emergency and sought financial assistance from the national government after flooding caused mudslides that covered roads and damaged homes throughout the region for the second time in as many weeks.
The Veneto region was on high alert Thursday as river levels were reported rising, ANSA said.
Water levels in Venice reached 50 inches and officials said they feared levels could rise. Hailstorms damaged vehicles and injured several people in the town of Trapani, ANSA said.
Ferry service between Naples and islands in the Gulf of Naples was suspended because of high waves.