Why the US has so many tornadoesThis video can not be playedTo play this video you need to enable JavaScript in your browser.Why the US has so many tornadoesCloseChris Fawkes explains what's behind the stormy weather in mid-western and southern US states this week.SubsectionUS & CanadaPublished12 May 2016Shareclose panelShare pageCopy linkAbout sharingRead description