UK is a tornado hotspot, according to University
researchers, who have found that more than
100 tornadoes a year hit the UK – more
per acre than the rest of Europe and the US.
In a Quarterly Journal of the Royal Meteorological
Society paper, geographers Joseph Holden
and Amy Wright argue that although there are
20-30 sightings each year, five times that
number of tornadoes actually hit the UK.
tornadoes are not reported because they are
not seen. But by modelling the conditions
leading to tornadoes, researchers can say
when they are likely to have occurred, even
if there were no witnesses.
Holden said: “The work allowed us for
the first time to establish the likely real
extent of tornadoes in the UK. We can now
get information on where tornadoes are likely
to be really occurring – whether they
were in urban areas and likely to be spotted
and cause damage or in remote areas and go
obtained details about past tornadoes and
the precise meteorological conditions at the
time they occurred and then created a model
which could say there would be a tornado when
those factors combined. When tested against
occurrences of when tornadoes were actually
reported it managed to get it right 86 per
cent of the time.”
the model was run using weather station data
for the period 1995 to 1999 it estimated 630
tornadoes, compared with the 122 actually
research also found that tornadoes are more
likely to hit the flatter south east of the
UK than the hillier north and west.
tornado is a fast moving rotating column of
air usually associated with a funnel shaped
cloud extending to the ground. In the UK tornadoes
are only classified as such if the funnel
cloud reaches the land. Tornado winds can
reach 300mph, but in the UK they are more
typically 70-120 mph.
are often caused by extreme atmospheric vertical
instability. This occurs when cold air overrides
warmer moist air and thus you get a strong
updraught. However, exact formation mechanisms
are still not fully understood.
tornado will often only last for a few minutes,
and may move a few miles across land. They
tend to have a diameter of 20 to 100 metres.
In the UK extremely intense tornadoes are
rare but in the USA occasionally vast tornadoes
track for over 50 miles and are over 1 mile
wide with winds over 300 miles per hour.