By Tom Frame
Last Wednesday (8 October) saw reports of several tornadoes in the UK – one even tore the roof off a house. I remember whengrowing up I always thought of tornadoes as something that occurred only in the USA – perhaps a school production of The Wizard of Oz had put this in my mind. So a few years ago (probably more than a few now), the first time I ever heard of tornadoes in the UK, I was pretty shocked. But just how common are these?
When I asked around I was told that it is often said that the UK has the highest number of tornadoes per year per square kilometre in the world. Is this really true? Interestingly a study published in 2003 (reference 1) seems to suggest that the UK has a fairly high number – but the highest? No …
It turns out that if you go by actual number of tornadoes observed , then the Netherlands has the most, Estonia second, Republic of Ireland third, the UK fourth and the USA fifth. Whereas if you go by an estimate of the true number then the UK jumps up to second place behind the Netherlands.
So tornadoes in the UK – not a big surprise.
The real reason that the USA is strongly associated with tornadoes is that it has the most intense and damaging tornadoes in the world. So whilst the UK has many, they are weak and short-lived usually causing only minor damage.
Reference 1
Dotzek, Nikolai. “An updated estimate of tornado occurrence in Europe.” Atmospheric Research 67 (2003): 153-161.
I feel a better way of doing this would be to take unit area (regardless of country) say 100 km^2 and then calculate the frequency within these boxes. Then see which country this box occurs in. The location and size of a country is an arbitrary human construct. This would give the answer to the question “where in the world are you most likely to see a tornado”. I would be interested then to see how some of the states in “Tornado alley” in the US match up to European locations.