30 June 2004                                                                                       Huntsville, Alabama

Recent articles by National Geographic, (“The Hard Science, Dumb Luck and Cowboy Nerve of Chasing Tornadoes”), CNN, (“Tracking Down Tornadoes”), and NOVA, (“Hunt for the Supertwister”) have focused on tornadoes in the Great Plains or central plains states.  Indeed, these tornadoes are the most spectacular in terms of visual impact, but they are not necessarily the most dangerous or the most numerous, as demonstrated by a recent VorTek study utilizing the SATT 3.0 software.

In the National Geographic article (April 2004, page 9), the statement is made that “forty percent of all tornadoes occur in the central plains states”.  This is an accurate statement and it leads to the obvious conclusion that the majority of the tornadoes do not occur in the central plains.  If not in the central plains, where do they occur?

In the CNN article, the statement is made “An area known as Tornado Alley – from Louisiana and Texas north to North Dakota and east to Ohio – regularly has more twisters than anywhere in the world”.  This statement neglects to note that of the top twenty most tornado prone states, eight states (Alabama, Georgia, Michigan, Minnesota, Mississippi, North Carolina, Pennsylvania, and Wisconsin) lie outside such a region.  This point is especially important when notice is taken that Mississippi ranks #1 in tornado probability.

The CNN article goes on to say that “The region from Oklahoma north to the Dakotas tends to have a well-defined tornado season with most twisters coming on late spring afternoons.  In the more southern states, tornadoes more likely arrive on winter mornings”.

The last part of this statement is just totally wrong.  If the writer was referring to the “southern states” associated with his Tornado Alley, then he would be referring to Texas, Louisiana, and possibly Arkansas.  For these three states, the most likely month for tornadoes is May and the most likely time of day for tornadoes in May is 5:00 to 6:00 p.m CST.  This is completely different from “winter mornings” as quoted from the CNN article.

In the NOVA article the statement is made “While the Great Plains gets the bulk of American tornadoes, other parts of the country witness them as well.  Florida sees more twisters than Oklahoma, though they are far weaker.  Cyclones also strike Colorado, and occasionally a ripsnorter will touch down in other states”.  Although the Great Plains are not specifically defined in the NOVA article, they are normally considered to consist of the eight states of Iowa, Kansas, Minnesota, Nebraska, North Dakota, Oklahoma, South Dakota, and Texas.  Of these eight states, two (North Dakota and South Dakota) are not ranked in the twenty most tornado-prone states, and thus only six of the top twenty states are in the Great Plains.  By comparison in the southeast seven states (Alabama, Georgia, Louisiana, Kentucky, North Carolina, Mississippi, and Tennessee) rank in the top twenty.  Clearly, something is lacking in the statement from the NOVA article.

There is also the perception that the most powerful tornadoes occur in Great Plains region.  Actually, in terms of the probability of encountering an F5 tornado, the state rankings are as follows:

             Rank                 State
                1                Tennessee
                2                Alabama
                3                Kansas
                4                Oklahoma
                5                Iowa
                6                Wisconsin
                7                Ohio
                8                Mississippi
                9                Nebraska
              10                Michigan

Notice should be taken that Tennessee and Alabama are at the top of list.