Lombardy region president Attilio Fontana said the incident was “very serious” and described the weather event as a “whirlwind”.
The boat overturned while it was on Lago Maggiore, a lake that sits across the border of Italy and Switzerland. Located on the south side of the Alps, it’s the largest lake in Southern Switzerland and the second largest in Italy.
It is a popular tourist destination and reports state both foreign and local tourists were on board, including a group of British travellers.
The boat appeared to experience significant damage. Videos from local firefighters showed fragments of wood in the water, which had broken off during the storm.
The whirlwind was part of a storm system that hit the northern region of Lombardy and forced delays at Malpensa airport.
Two people were taken to hospital in “moderately critical” condition, three were taken in “not very critical” condition and 15 were treated at the scene and did not need to be taken to hospital.