Tornado formation and rating.

A tornado is defined as a quickly rotating column of air that is in with both the ground and the clouds.

Tornadoes form from large storms known as supercells. Not every supercell leads to the formation of a tornado, but they contain the most important ingredient in the tornado recipe: a vortex of spinning air.

Let’s imagine a supercell with its vortex of spinning air. As the supercell gets larger, the vortex begins to tilt, pulling warm air and moisture upward, and pushing out cold dry air in the direction of the ground. The water vapor causes the vortex to gain mass and a funnel cloud forms, one of the first signs that a tornado is brewing.

The cold air being pushed downward counters the funnels upward spiral, decreasing the size of the cloud and thus increasing its speed. With enough pressure from this downdraft, the funnel cloud is forced to touch down and a tornado is born.

Fortunately, most tornadoes are pretty harmless and have a lifespan of only a few minutes. However, when they break away from the average, Tornados can be some of the most destructive weather events in the world. The worst of them last for hours, reach up to 480 km/h and span miles in diameter.

In general, tornadoes fall into three types: weak tornadoes, strong tornadoes, and violent tornadoes.

A tornado's type is based on its size, how long it lasts and how much damage it causes.

- Weak tornadoes usually last less than 10 minutes, have winds less than 160 km/h and cause damage such as broken tree branches and damaged roofs. The majority of tornadoes are weak. The estimate is around two thirds in total. This category includes those in the first two categories of the Enhanced Fujita Scale: EF0 and EF1.

-  Strong tornadoes can last 20 minutes or longer and have winds of 177 to 330 km/h. Strong enough to badly damage mobile homes and automobiles. Around a third of tornadoes are strong and they cause about 33 percent of all tornado-related deaths. Strong tornadoes include those in the next two categories of the Enhanced Fujita Scale: EF2 and EF3.

- Violent tornadoes can last over an hour and have wind speeds greater than 330km/h. These tornadoes can pull cars and houses into the air and carry them over long distances. While violent tornadoes are the least common, they are the deadliest, causing over two-thirds of all tornado-related deaths. A violent tornado is part of the last two categories on the Enhanced Fujita Scale: EF4 and EF5.

Living in , the strongest Tornado recorded last year (2023) was an EF1. In 2022, we had a few EF2 Tornados but nothing stronger has developed in recent history.

In the USA, there are more Tornadoes of greater strength. Especially in so-called tornado alley, where most of the Tornados in the States take place.

But what does have in common with tornado alley?

Mostly, it’s because they are stuck between different air fronts of varying pressure and different temperature and humidity.

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These differences in air pressure and temperatures are the birthplace of supercells. Typically, supercells are found in the warm sector of a low-pressure system propagating generally in a north easterly direction in line with the cold front of the low-pressure system.

These supercells precede the development of tornadoes that could not form without them.

Other European countries that have tornadoes include and Italy (in the north).