Britain turns into a tornado hotspot with 100 twisters a year

Tornadoes are five times more likely to hit Britain than the United States, research has revealed. A geographer who describes himself as a "fair-weather scientist" has discovered that Britain is in fact a tornado hotspot - receiving more of them per unit area than the US or Europe.

Tornadoes are five times more likely to hit Britain than the United States, research has revealed. A geographer who describes himself as a "fair-weather scientist" has discovered that Britain is in fact a tornado hotspot - receiving more of them per unit area than the US or Europe.

At least 100 tornadoes strike Britain each year, more than three times as many as had been thought, according to calculations carried out by Dr Joseph Holden, working with Amy Wright at the geography department of the University of Leeds. The research was published in the Quarterly Journal of the Royal Meteorological Society. Most tornadoes are not reported because they remain unseen - but calculations by the scientists showed that the correct weather conditions to create a tornado occur frequently in the UK. A tornado is defined as a fast-moving rotating column of air, usually with a funnel-shaped cloud that extends to the ground. In the UK, the definition requires the funnel cloud to reach the land.

Between 20 and 30 tornadoes are sighted in the United Kingdom each year. But by modelling the pattern of winds and rain needed to create one, Dr Holden said that there were many more which occurred but went unnoticed, because they are mild compared with the "twisters" in the US. Instead they may take place without any witnesses.

"In the US they can be half a mile wide and have winds of up to 300mph at the outside," said Dr Holden. "But in the UK the largest would probably be a few tens of metres wide, with winds of up to 120mph. In the US they use Doppler radar systems to detect them, which we don't have at all in the UK."

Yet British tornadoes sometimes cause significant damage: in January 1998 one hit the town of Selsey in West Sussex and caused £10m of damage; the same town was hit in October 2000, when two people were injured and more than £500,000 of damage caused.

The risk could also be rising because of global warming, which climatologists believe will make Britain stormier. Dr Holden said that while the risk might increase, the size of British tornadoes would probably stay the same: the UK generally has smaller tornadoes than the US because "we don't have the vast wide tracts of open land needed to build up the really big ones".

Although trained as a hydrologist, Dr Holden was inspired to research the subject after seeing a tornado while he was walking in the north Pennines. "You look at these things and are awed by the sheer ferocity of nature," he said. He and Ms Wright studied details of past tornadoes and the exact weather conditions at the time, and then created a model that could predict if a tornado would occur given a set of recorded weather conditions.

When tested against reports of tornadoes, the model was correct 86 per cent of the time.

Running the model using weather-station data for the period 1995 to 1999 suggested that the UK had sustained 630 tornadoes, rather than the 122 reported. Dr Holden said: "We can now get information on where tornadoes are likely to be really occurring."