General Discussions: ASK John: TORNADOES

By myq on Wednesday, August 06, 2008 - 04:48 am: Edit Post

Hi John,

The other night, the Chicago area was hit with violent weather setting off the air raid sirens which is quite rare and spooky. Although there was no downtown tornado, the atmosphere must have been quite ripe.

Growing up as a kid, we were always told that a tornado to hit the city was near impossible given the height of city buildings blocking air flows to thrwart the progressive development of a tornado or, Lake Michigan was also a deterrent to tornado development (given this was a large mass of water close to the city which also thwarted tornado development.

Are either of these true or just myths to keep a young kid from going into hysterics.

If they are true and retard tornado development, with today's seemingly changing weather forces, I'm not sticking around but heading for the bunker at the next siren sound.

By admin on Wednesday, August 06, 2008 - 11:20 am: Edit Post


The idea that the tall buildings in a downtown setting will inhibit tornado growth or formation is a total myth. Just ask the folks of downtown Nashville that saw a tornado roll through a few years ago. The powers that drive a tornado are all housed in the parent thunderstorm and that all happens well above the level of even the tallest buildings man builds.

As for the lake. A large body of cold water can inhibit thunderstorm developent/intensity. However, the water needs to be cold, say under 60 degrees to have a significant effect, and the thunderstorm needs to travel over the lake. Since most of the weather in the Chicago area arrives from the west (or NW or SW), the thunderstorm would not travel over the lake before arriving in town, so it would not have an impact on the storm before it hits Chicago.

Here where I live, there it lots of cold air off to our west and many times thunderstorms will "flame out" as they roll off the MN shore and head our way. This is a big reason for the lack of severe weather that we see here in the Keweenaw, vs the amount that is seen just to our south a bit.


By einne on Thursday, August 07, 2008 - 07:45 pm: Edit Post

kendall county got hammered. town of Sandwich got the worst i hear. (LaSalle county.) small towns

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