05 July 2018

Tornados in The United States

Tornados (with speeds up to hundreds of kilometres per hour) in The United States appear more and more frequently. The number of tornados per outbreak has also been rising in the last couple of years. An outbreak like this usually doesn’t just last a couple of hours, they often take one to three days. 


Why the tornados occur more frequently is still a mystery for scientists. Often it is thought that the climate change could be the reason for this. However, a recent study showed that there is no substantial evidence for this yet. Facts that are ascertained during this research do not belong with the facts of the climate change.  


Michael Tippet of the Columbia University School of Engineering and Applied Science has the following to say on this subject: “This research calls for new questions on what the effects of climate change will be for the heavy storms and what the cause is for the latest trends we see. The fact that we don’t see the meteorological signature of global warming in the changing outbreak statistics can mean two things. Either the recent rise in outbreaks has nothing to do with the global warming, or the global warming has an effect on the tornado outbreak that we don’t yet understand. Which is an unexpected result.”

The origin of tornados 

What they do know is how a tornado is created. A couple of factors have an influence, namely; intense winds high in the sky, humid air on lower points in the sky, and the ground needs to be warmer than the air. The difference in temperature between the air on the ground and the air at 10,000 kilometres can differ up to 70 degrees in The United States. Warm air will rise, and how bigger the difference in the temperature, the faster this process will go. When a tornado is created the air starts rising so fast that a small low-pressure area is formed on the ground. The air around this area starts spinning and is sucked towards it. You can compare this to water that leaves a bath tub, then a small vortex is created as well. 

Tornado Alley 

The reason for the frequent occurrence of tornado’s in The United States is the combination of cold and warm air. Warm air enters The United States through the Gulf of Mexico. The cold air meets the warm and dry desert air from Mexico, especially above Texas, Alabama, Missouri, Kansas, Nebraska, Iowa and Arkansas (Also called Tornado Alley). The cold air comes all the way from Canada  


Tornados are very unpredictable at forehand, and it is definitely not able to predict when and where they will appear. This makes it even harder for Americans, since they cannot prepare themselves for the tornado. Annually The United States gets about 1000 tornados. Not all of them are evenly heavy of course. The intensity of a tornado is measured on a scale of Fujita, in which category 5 is the highest intensity. When a tornado is category 5 the wind speeds will rise up to 400 kilometres per hour.