Tornado from Chicago?

[Robert Dewey]

It doesn't quite work that way imo at least. The period of study needs to be as long as the frequency of events being considered to get reliable results. Since the super outbreak is at best a 120 year anomaly, you shouldn't consider it in a study that only spans 75 years. Also, the use of the terminology "tornado alley" implies a region of favored frequency of occurence of tornadoes, doesn't it? Really, even the signal across the deep south is low frequency - but more on a 5-10 year period than 150 years.

Glen

I would agree, it's tornado days per century, yet the data doesn't span that far - So, does that mean they are extrapolating data for the remaining years, or simply not using that data? Either way, it skews the study. I also agree with Mike G., that most reports prior to 1950 may be rather inaccurate - I would tend to move that date up to 1970-ish, or up until the Fujita scale was widely used - Since this study uses the Fujita scale (F2 or greater). In my opinion, the main 'alley' is located from northern TX into NE and western IA... But that doesn't mean there aren't other hotspots, as some have noted.

 

[Glen Romine]

Agreed, there is no doubt that the historical tornado database leaves a lot to be desired - but in the Brook's plot shown is only F2 and greater events - and despite some events likely being overrated, there are a lot more 'targets' for tornadoes these days - so these opposing effects help to some degree to offer some validity to the historical database. If you look at significant tornado days per year over the period - numbers are really pretty steady since the early 1920's.

From NSSL


Glen

 

[Fabian Guerra]

We have not had a tornado in the city proper for a while (1967 as Dan pointed out). However, there have been several tornadoes in "suburbs" of Chicago or on the outskirts of the city. Also, there are usually many tornadoes every year within a 1-4 hour drive from the city. For a storm chaser that's a hop, skip and a jump...especially if you already traveled all the way from France.

Fabian

 

[David Draun]

4/20/2004 Warm front action, just SW of the city, a big surprise for forecasting that day.

 

[Alex Lamers]

If you want to chase it would be best to the southwest of Chicago in more flat, open area and where the hills will be slight and rolling if you can find some. Get close to the Wisconsin Border or if you stay in the metro areas then you could have a problem with various obstacles. If Illinois is your target then I would go with West-Central to Central Illinois particularly in the Spring and early Summer. (April - June).

Although, I would like to make a point that people have chased and been successful in just about any type of geographical setup...take for instance Wisconsin's Kettle Moraine which is notoriously hilly and does have some densely wooded areas. Not exactly optimal but I have seen some great shots come out of this area. Make the best out of what you have but ALWAYS and I repeat ALWAYS avoid major metropolitan areas such as Chicago. The last thing you want is a traffic jam or exit confusion or what-have-you in a dangerous situation.

...Alex Lamers...

 

[DELIGNY Vincent]

thank you very much for your answers!!!!!
i'm happy ; the chicago state is great for tornados!
i've find there picts:


[Broken External Image]:http://site.voila.fr/fryz2004/tornadeUSA.jpg

:wink: