I read somewhere that 97% of all tornadoes occur in the USA. I was wondering why this is. Also, where do the other 3% occur?
Eric
Well, the stats you heard are a little bit stretched, even though tornados are a mostly North American phenomenon.
Every so often, a tornado will hit Bangladesh and kill a few thousand people. Most deadly tornado happened there, killed about 1,100, IIRC.
Would the Bangladesh fatalities be a consequence of population density and low-grade housing?
One of the factors is “Tornado Alley” as explained by Cecil’s Dope referenced above. This geological phenomenon appears to be unique to the south/central U.S.
Living here in Oklahoma, one gets used to picking up on the signs of a tornado day.
But, it isn’t only in Tornado Alley that devasting (F-4, F-5) tornados can form. If the weather conditions are right, a tornado can form any where, any season.
Fujita’s research into tornados and hurricane eye walls is fascinating. Apparantly, smaller, fast moving vortices can form around each other becoming a larger vortice. Picture a bunch of tiny tornados following each other in a circle. That’s what a hurricane eye wall and a large tornado may, in fact, be.
Real time research is hard to do because of the transient nature of storms. Which is why storm chasing has grown in popularity.
Check PBS for the Nova show on tornados and Fujita. You will be amazed.
And, yes, asterion if unprotected in a large tornado, death is near. With wind speeds as high as 318 mph (May 3rd, 1999 F-5, Oklahoma City), a blade of grass can penetrate a brick wall, as I witnessed in the clean up / rebuild after that storm. Imagine what a small piece of wood could do to your head at that velocity.
When I was living in Ottawa (1971-77) there were several instances of tornado activity in the Southern Ontario area. No lives list that I recall, but perhaps some property damage (falling trees, broken power lines, tires blown off of the roofs of trailers…)
Here are some pictures from a tornado at Pine Lake, Alberta (roughly halfway between Calgary and Edmonton). They have had two big tornados within the 10 years. A summer camp there, that I went to as a child and that my grandfather is still involved with, is building a new arts and crafts centre that will also provide tornado protection.
Also, back in the mid to late 80’s there was a tornado in Edmonton that killed something like 29 or 33 people.
Yes, but possibly also due to the fact a large part of Bangladesh is the Gange delta, hence most of the country is at a very low altitude and an event like a tornado can probably result in catastrophic inundations.
Hey, I really don’t think a tornado in Canada should be counted as anything more than spillover from the U.S.
I was in England a couple of years ago, when they had one. It did very little damage, but it scared the heck out of them. It turned over a caravan and put a dent in it. Here in the states a tornado turns whole trailer parks into scrap metal.
That’s because there is a proven affinity between tornados and trailers/mobile homes. A tornado, as soon as it is born, is automatically drawn to trailer parks. I think it has something to do with electrostatics.
