Tornadoes in the British Isles

Tornadoes are a form of extreme weather hazard that is particularly common in the USA, but they have been reported on every continent except Antarctica. This article looks at British tornadoes and explores some of the main differences between those in Britain and the USA

Sylvia Knight and Kelsey Mulder

A tornado in Norfolk

It may surprise you to know that you are more likely to see a tornado in some parts of the British Isles than you are to see one in most of the USA. In England the density of occurrence is 2.2 tornadoes per year per 10,000 km2. Over the entire USA the average is 1.3 per year per 10,000 km2. However, if you focus in on Oklahoma, part of the US ‘Tornado Alley’, the figure rises to 3.5 per year per 10,000 km2. British tornadoes don’t usually cause fatalities, although minor injuries and damage to property are not unusual. US tornadoes can be much more destructive.

In the USA tornadoes are commonly produced by ‘supercells’. Over the last 10 years, our understanding of how supercell tornadoes form has changed considerably (see Box 1).