What is a tornado?

Have you ever seen a tornado?

If you answered ‘no’ to that question, then I’m willing to bet you have!

Just fill your bath with water and then take the plug out. You’ll see a ‘tornado’ as the water disappears down the hole. OK so it’s not a ‘tornado’ as such but it’s a ‘vortex’, which is essentially what a tornado is.

A vortex is the most efficient way of moving a fluid from one place to another quickly.

Air is a fluid, just like water and tornadoes form as air starts to spin due to winds below a cumulo-nimbus thundercloud blowing at different speeds. This causes the air to start spinning horizontally. If this gets caught in an updraft, the updraft tightens the spin; it then speeds up and tilts towards the ground.

The central and southern US states see the most violent tornadoes in the world due to a unique combination of geographical and meteorological circumstances. This region, from Texas through Oklahoma and Nebraska to South Dakota and Iowa is known as ‘tornado alley’. Here cold dry air moving south and east from Canada and the Rocky Mountains interacts with warm moist air from the Gulf of Mexico, giving perfect conditions for severe "supercell" thunderstorms to develop, with a risk of producing tornadoes, especially in late spring and summer.

As tornadoes develop we see funnel-shaped clouds extending from the base of the cloud and it is only when these funnel clouds touch the ground do we get a tornado.

Rather like the hurricanes in the Carribean, the greatest danger is not so much the wind itself as the debris being blown around by those winds, which can be in excess of 200mph.

It is claimed that the UK getsmore tornadoes per square kilometre than the USA, but not more tornadoes in total. On average, around 30 tornadoes are reported each year in the UK, although these are thankfully much weaker than their American counterparts.

In the meantime thoughts are withthe victims of the Oklahoma tornado.