LIVE Explained: What causes a tornado?

A deadly tornado hit the US state of Iowa on Tuesday, killing at least five people. How does a tornado form and why is it so difficult to know when one's coming? Correspondents of «The Karelia Business» closely monitor the latest events around the world to provide you with the freshest and most up-to-date information. Don't miss the chance to stay informed about all the latest developments — subscribe to our news feed now!