[Vwdiesel] Tornados and and Huricanes

[travis gottschalk]

I won't argue with someone that is tornado alley but my physics teach mentioned the example of a grocery store in MN that the brick wall blow outward (sucked out) and there was a whole pile of stacked cans next to the wall that stayed in there position. That is how he explained the pressure. Not to say a house doesn't have different weaknesses then a brick building. 
Travis G. 

> I sent this earlier but realized that it went in Rich text not 
plain text and therefore didn't make the list.  So....It turns out the 
idea of opening windows in a house during a tornado to equalize pressure
 is a myth.  Pressure differences do not destroy houses in a tornado, 
the wind does.  Unless the house is hit directly by the funnel and 
destroyed, damage to the house is generally the result of the 
penetration of the outside structural envelop and then a failure of a 
main structural component, usually the roof ( this is true whether you 
are talking about a tornado or a hurricane).  Once the roof is gone, the
 rest of the house generally follows.  Turns out the houses have two 
main areas of weakness that let wind into the house:  the windows and 
the garage.  Loose either of these and the wind will enter the house and
 peal the roof right off.  Many insurance companies and governmental 
entities along the hurricane coasts now require special windows that are
 specially designed not to be shattered by flying debris or blown out of
 their frames.  Garage doors are also required to be much stronger to 
prevent them from failing.  BTW, your car is about the worse place you 
can be in a tornado.  Winds can and do easily pick cars up and throw 
them around like rag dolls.  Yesterday's storm here in Dallas picked up a
 fully loaded 18 wheeler, spun it around and tossed it into a building. 
 BUT don't get under a highway underpass either, the passing tornado 
creates a wind tunnel effect that can either blow you right from under 
the bridge or kill you with fast flying objects.  Since I live in 
tornado alley (Texas) and I am a science teacher (geology), I like to 
keep up with all the latest stuff.
> 
> 
> Sep 9, 2010 07:36:02 PM, tgott at hotmail.com wrote:
> 
> 
>
 I wouldn't leave the windows down as they always have rain. It is part 
of a rain cloud. If not rain then there will be hail. The reasons for 
keeping the windows open would be for a house or building because of the
 pressure difference from the fast air and the calm air (think chimney 
effect only greater). Most houses blow out as calm air has more pressure
 and blow down or away from the wind. Cars have strong enough shells and
 windows and arn't anchered down so with or without the car is going to 
blow away if to close to the funnel. I had a good physics teacher 
explain this and I lived where there were plenty of tornados to study 
the aftermath of them. Don't know much about the huricanes. Windows are 
boarded to prevent debree damage I assume since they cover so much more 
area. Windows on a tornado are the least of the worries as keeping the 
house standing is more of a challange. 
> Travis G.