Tornadoes – What Are They, What Causes Them?

Tornadoes often strike fear in some, but are mentioned as beautiful sights to see for others. But what exactly is a tornado? How does it form? Why does it form? We will talk about different aspects of Tornadoes in this post.

Tornadoes usually spark from severe thunderstorms associated with a cold front or warm front. But at times they can form from Hurricanes and other tropical related weather phenomena. This is due to the fact that as Hurricanes come over land they meet the friction of the ground/landmass, this at times causes the thunderstorms inside the rain bands of the Hurricane to rotate. Usually these are short lived hurricanes, but can produce a measure of damage.

Funnel Clouds are generally harmless, but when they touch down it can become a deadly tornado.
Funnel Clouds are generally harmless, but when they touch down it can become a deadly tornado.

Tornadoes are formed due to rotation in the upper atmosphere of a thunderstorm, this causes the formation of a meso -cyclone. In a typical severe thunderstorm usually the rotation is Horizontal, but at times this goes vertical and this is when you usually start to see the formation of a funnel cloud.When a funnel cloud touches down to the surface of the ground it becomes a tornado. But what are the ample conditions for a tornado to form?

*Note: A Funnel Cloud is not a tornado, however when seeing one, you should not treat it lightly. As at any moment the generally harmless funnel cloud can touch down and become a devastating tornado. 


Super-cell Thunderstorm With hook echo (Picture of NOAA)

Well typically tornadoes form in what are called super-cell thunderstorms. To your left you will see what is one example of the strongest form of a supper-Cell thunderstorm. When they contain a hook echo (A), that is where the strongest rotation is in the thunderstorm. Usually that is where the tornado is located. The strongest tornadoes usually are in such thunderstorms which contain hook echos.

Which brings us to our next point. The strength of tornadoes. This scale has been revised over the past decade. This scale is called the “Enhanced Fujtia Scale”.  But the strongest tornadoes (E-F5) are not that common, and as mentioned before usually happen in such thunderstorms that have hook echoes on them. Such tornadoes can last hours and cover over 20 miles worth of land. They can also be up to a mile wide as well. This makes it all the more important that you know how to respond to such weather when it arrives. (For a tornado preparedness guide click here)

FUJITA SCALETornadoes in General Commonly occur in what is called “Tornado Alley“. This includes the states of Florida, Texas, Oklahoma, Nebraska, South Dakota, and North Dakota.  However Tornadoes can occur anywhere, when the conditions are ripe. Some ripe conditions for tornadoes are:

  • Warm-Hot and Humid Weather
  • Dew point temperatures High
  • Tight gradient between Warm Moist Air and Dry Cooler air masses
  • Jet Stream influence on the Weather system
  • ***Hurricane Landfalls, which create there own spin as covered earlier***

These are conditions that usually start to occur in Spring in the Middle section or Tornado Alley a lot. Which is where most tornadoes usually form. Tornadoes can also occur in other places where these weather conditions exist. Tornadoes can be a scary event, but knowing about them can help ease some of the fear, and more importantly help you prepare for them. We hope this article has helped to inform you the basics about tornadoes.


Dante' Brown-Royal

Dante' Brown-Royal

Hello, I am Dante' the CEO/President of Weather Advance. I most of the time specialize in Winter Weather and winter forecasting. I also am pretty decent in predicting severe weather and tracking hurricanes. Howevere usually that's not my forte. I will strive to always give you the most accurate updates possible, and information possible when it comes to the weather!

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