Sunday, June 23, 2013

Hiding From Tornadoes Under Bridges


Every Tom, Dick, Harry, and Mark have asked me about the “overpass” scene in the movie, “Man of Steel.” Got to see the movie yesterday and, I have to say I wish the scene wasn’t there. I’d like to think people would take the advice of meteorologists not to do this but given the reports of people crawling up under overpasses during the May 31 El Reno Tornado, it appears they do not.

Where did the “take shelter under an overpass” business start? 

On the Kansas Turnpike, between El Dorado Lake and Cassoday, April 26, 1991. KSNW TV photographer Ted Lewis and reporter Gregg Jarrett were coming back to Wichita from covering a story in northeast Kansas. They didn’t even have the car radio on when they encountered a tornado. It was the fifth in a series of tornadoes (the fourth was the horrible Wichita-Andover tornado that killed 17) spawned by a single supercell. There are relatively few exits on that part of the Turnpike the the area is completely rural.

The raw video shot that day is below:


Some comments about what you are seeing:

As the tornado approaches and Gregg and Ted start to escape, they start dodging the debris falling from the sky that is accumulating on the road. That, obviously adds to the sense of urgency. 

When they get out of their cars, starting at 3:34, you can hear the “waterfall” sound that I have heard around tornadoes.

At 5:29, when Gregg says, “here comes another one” he is feeling the gust of wind known as the “rear flank downdraft” not a second tornado.

Here is the irony: The bridge probably did save their lives because of its unique construction. I have taken television crews to where they hid from the tornado maybe one bridge in one hundred is constructed this way. As they crawled up on top of the concrete they were behind solid steel with a second girder behind them. 

You can see a second angle of the block, connection, and girder here:

Getting away from their cars was the right thing to do. In the background of the video you can see a minivan, occupied by a family, being tossed around by the tornado. The occupants were seriously injured. They might fare somewhat better today with side curtain air bags but that questionable because they were being thrown around over a period of several seconds rather than a single impact.




So, so what should you do when a tornado approaches you on an open highway?

The minivan is tossed around on the side of the road facing the tornado. Get away from your car by several tens of feet before you descend to lower ground. The best advice is I know of is to take shelter on the side of the road away from the tornado as low as you can get but not in a drainage ditch or storm culvert/sewer. 

2 comments:

  1. so if you are in a depression to be clear as you can be of debris in the air stream, a 100-200mph turbulent flow over you will be your best chance?

    Any heavy debris that hits you will probably do you in I would think, but the wind in of itself would not be lethal.

    So would the air stream "suck" you up, or would your mass hold you down and not make you a bit of debris till you die?

    I smell a Mythbusters episode type question. Open field with depressions shelter from tornado velocity winds. I know an episode that focused on high winds where the Mythbusters episode had a 747 supply high force winds suggested they could remain on the ground in one place. They even devised a shelter to test that hypothesis and tested it.

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  2. Jim,

    The best "prevention" is to be proactive so as not to get you a situation where the only options are bad and worse."

    In the May 19 Clearwater tornado (see: http://meteorologicalmusings.blogspot.com/2013/05/wichita-avoided-catastrophe.html ) people were complaining about traffic jams. This had nothing to do with television weather reports; there were just too many people on the road when hail started, people then stopped under overpasses, blocking the highway, etc.

    This blog and every television and radio station in the area had been explaining all day the high risk of tornadoes, a tornado watch was out, etc. WHY WERE ALL THESE PEOPLE DRIVING AROUND?!

    There is an element of personal responsibility here. When you are under a tornado watch and a severe thunderstorm warning already in effect (as there was May 19) you should be at home or work or you should shelter in place at (for example) a shopping mall. Driving around is the last thing you should be doing.

    But, if you are caught in an auto, this is the best advice we can give.

    Mike

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