'Tornado Hotspot' In Home Counties


A genteel corner of the Home Counties has been pinpointed by scientists as Britain's version of Tornado Alley, the area of the United States hit by frequently devastating "twisters".

An area between London and Reading in Berkshire is the most likely part of Britain to be hit by the swift, violent weather events, according to a team from the University of Manchester.

They have used eye-witness reports of UK twisters over a 32-year period to update a map of UK "tornado hotspots" for the first time in 20 years.

The UK experiences on average 34 tornadoes per year, the most per area of land mass in the world, the scientists say.

The strongest seen were categorised as F2 on the Fujita scale used to assess their power, with winds of up to 157mph (253kph) compared to the F5 storms seen in the US where windspeeds can exceed 300mph (483kph), they reported.

Kelsey Mulder, of Manchester's school of earth, atmospheric and environmental sciences, the report's lead author, said: "F2 tornadoes are still quite strong and are perfectly capable of causing damage and injury. For example there was the twister that hit Birmingham in 2005 that caused 19 injuries and £40m of damage.

"Because tornadoes are capable of causing such damage it is important that we have some kind of idea where they are most likely to hit."

The 130mph twister that struck Birmingham's "Balti Belt" in July 2005 swept through the Sparkbrook, Balsall Heath, Moseley and Kings Heath areas uprooting more than 1,000 trees and causing extensive damage to homes and businesses.

The paper, for the June edition of the journal Monthly Weather Review, analysed land-based tornado data from 1980 to 2012.

It found the area most likely to be struck was west and south west of London, which had a "6% chance per year of a tornado occurring within 10km of a given location". But you may live there for some time - scientists also described this as a "one in 17-year event".

Next most likely to be affected was an area from Bristol through Birmingham to Manchester (5%), a strip starting north east of London and running to Ipswich in Suffolk (4%) and the south Wales coast around Swansea (3%).

Some 95% of the storms were categorised as F0 or F1 tornadoes, meaning windspeeds of up to 112mph (180kph).

The peak season for tornadoes was May to October, with 78% affecting England. The scientists found large parts of Scotland, Wales and Northern Ireland experienced no tornadoes at all in the period studied.

US-born scientist Ms Mulder, who decided to study weather after her home town of Boulder, Colorado, was hit by a small tornado when she was just six, added: "It seems that most tornadoes in the UK are created along long, narrow storms that form along cold fronts, whereas most tornadoes in the United States are created by isolated storms, which are more similar to the beautiful supercells you see in the movie Twister.

"Even in the United States, tornadoes formed along cold fronts tend to be weaker than those formed from supercells. That could be one reason why tornadoes in the UK are much weaker. But the process for how tornadoes form along cold fronts is not yet very well understood."

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