It is a myth that tornadoes never hit big cities. Below is a picture of a tornado that ravaged downtown Miami Florida on May 12th, 1997. Tornadoes have a long history of hitting big cities and when they do, they usually cause a great amount of damage due to the population density. They can form pretty much anywhere at any time. One was even documented in the Rocky Mountains at an elevation of 10,000 feet. However, they usually form in the Midwest during the the springtime.
It’s a matter of population density, statistics and climate rather than a city’s physical attributes that make it seem as though they rarely hit heavily populated areas.
Climate plays the biggest role in tornado formation. For example, the Midwest nicknamed “tornado alley” has a good supply of warm moist air from the Gulf of Mexico, cool air from the north, and warm dry air from the west. These three ingredients greatly increase the odds of a tornado forming. This is much different than the more consistent weather of the west coast or the consistently cooler climates to the north (although tornadoes have been reported in these locations too).
Within tornado alley, the population density is considerably less than the east and the west coasts. Therefore, the odds of a tornado hitting a populated area is less than say, New York or Los Angeles. If the same number of tornadoes spawned in these two states as does in Kansas and Oklahoma, this article wouldn’t need to be written. Big cities would constantly suffer tornado strikes.
Lastly, the “downtown” part of a big city where the tall skyscrapers are situated is usually pretty small target in comparison to the city as a whole. But that doesn’t mean downtown areas are immune or somehow repel tornadoes. In fact, a house outside the city with a much smaller footprint has even less a chance of getting hit only because it’s an even smaller target.
Thankfully, big cities don’t get hit all that often, but it’s not the physical attribute of the city that somehow prevent them from forming or repel them. Tornadoes can form just about any place. In fact, a tornado was documented above 10,000 feet by a hiker in the Utah mountains and another in Colorado just off Pikes Peak (14,000 foot mountain). I remember as a kid hearing about a tornado that formed off the coast of Southern California near Palos Verde and another that briefly touched down in Sunnyvale, CA (the heart of Silicon Valley).
Here’s a list of big cities that have been hit by tornadoes in recent times:
- Birmingham, AL (2011 video)
- Dallas, TX (1997 video, 2010 video, 2011 video)
- Houston, TX (2012 video)
- Jacksonville, FL (2009 video)
- Los Angeles, CA (30 tornadoes since 1918)
- Miami, FL (1997 video)
- Oahu, HI (2011 video)
- Oklahoma City, OK (F5 Tornado)
- Salt Lake City, UT (1999 video)
- St. Louis, MO (22 tornadoes in the past 40 years)
- Sunnyvale, CA (right smack in the middle of Silicon Valley)
- Witchita Falls, KS
St Louis is a large city that sprouted up in Tornado Alley, and it has a long history of destructive tornadoes. Approximately 22 have hit the city in the past 40 years alone. One could make the argument that tall skyscrapers could affect the air flow patterns needed to sustain a tornado. But it’s probably unlikely that a few buildings which are a few hundred feet in size would have much of an affect on a supercell which can grow to heights in excess of 50,000 feet (9 miles) and be as big as Mount Everest. Even a tornado itself can be as wide as a mile or more. So as of this writing, no scientific evidence has proven that cities repel or prevent tornado formation.