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The Safety Myth About Highway Overpasses

By Jennifer Wojcicki @yourmetjenny May 22, 2018 8:46 am CDT

As we enter into a very mild start to March, it’s time to start thinking about the impending severe weather season. Here at Weatherology, we like to pride ourselves in giving you the best knowledge on how to stay safe during severe outbreaks, and to put to rest common myths associated with certain safety issues. One of the main ones that comes up every year is the idea that hiding under a highway overpass is the safest place to seek shelter when a tornado is approaching.

THIS IS FALSE.

If a tornado is passing over a highway overpass, it ends up creating an incredibly strong “wind tunnel effect.” Winds end up channeling under the overpass, creating higher wind speeds. Not only this, but if you seek shelter in the small crevice that joins the tilted ground to the overpass, wind speeds of the tornado are higher here already since they are faster above the ground than they are at ground level.

 

You can think about it this way- if you turn on a hose (with no nozzle) to full force, it shoots the water pretty strongly. Now, take your thumb and cover the hose 95 percent. What happens? Not only does the water try to push your thumb away, but it gets channeled and the force of the water becomes stronger and faster.

Another thought is that the overpass will keep you safe from debris. This is also false. Debris will go wherever the tornado goes, and then some.

Along with that, many people want to place their vehicles under the overpass for added shelter. If a tornado passes over, it can cause a lot of damage, not only to the vehicles by creating a pileup, but by blocking the roadways to possible emergency responders that need to get through.

If you ever find yourself in your car when a tornado approaches, do not try to outrun it. The safest course of action is to get out of the tornado’s path and seek shelter in the lowest floor of the nearest sturdy building. If you’re not around a building, lying flat in a ditch or ravine will offer protection against flying tornadic debris.

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