By Paul Homewood
Ben Fogle, the Eco-Adventurer, has been visiting Joplin, Missouri to see the devastation caused by last year’s F5 tornado. Writing in last week’s Sunday Telegraph, he says :-
Local storm experts have predicted that the high temperatures out in the Gulf of Mexico are a grim prelude to another bumper season of tornadoes.
We have already seen that, despite last year’s rash of storms, the trend in recent decades has been to less tornadoes in the USA, as the chart below shows. (See report here). This has happened despite warmer waters in the Gulf.
So what does cause tornadoes? NOAA themselves admit nobody really knows :-
The classic answer–"warm moist Gulf air meets cold Canadian air and dry air from the Rockies"–is a gross oversimplification. Many thunderstorms form under those conditions (near warm fronts, cold fronts and drylines respectively), which never even come close to producing tornadoes. Even when the large-scale environment is extremely favorable for tornadic thunderstorms, as in an SPC "High Risk" outlook, not every thunderstorm spawns a tornado. The truth is that we don’t fully understand.
Nevertheless the three conditions mentioned are all integral factors. A look at the temperature map last May, when Joplin was hit, shows the preponderance of cold air to the west and north of Missouri.
May 2011 Temperature
This GISS map also shows the temperature contrasts at that time.
Now contrast with this map of Spring temperatures for 2000-10, when tornado occurrences were at a minimum.
Gulf temperatures were as warm as they were in 2011, but it is quite noticeable that, last year, colder air penetrated much further south and east.
There were 79 F3+ tornadoes last year. Disastrous as this was, it was much worse in 1973, when, again, there was a mass of cold air to the west, as can be seen below.
Please, Ben, don’t make simplistic comments about events you don’t understand, particularly ones that can have such tragic consequences.
Footnote
I just saw Ben last night swimming with crocodiles in his new TV series. I wish I had a tenth of your courage. Well done, mate!