Five years ago, on 17 November, 73 tornadoes barrelled across the US midwest, killing 11 people, injuring more than 100 and costing about $1.6bn in damages. It was an exceptional event but in future the region may have to brace itself for more tornadoes.
The most tornado-prone part of the country extends from northern Texas, through the Great Plains of Oklahoma and Kansas then into Nebraska. Some of the most powerful storms spin up in this area, known as Tornado Alley.
But now it seems Tornado Alley may be moving to the east. In a study published in the Nature journal Climate and Atmospheric Science, Vittorio Gensini and Harold Brooks say that while the annual number of tornadoes in the US has remained roughly the same since 1979, there has been a shift from the Great Plains towards the midwest and south-east.
The reason for this is not clear but the scientists say it is consistent with a warming climate. This shift is of particular concern because the new Tornado Alley is more densely populated, with a greater proportion of people living in highly vulnerable mobile homes.
