On the first page, we mentioned an average of 800 tornadoes in the USA occurring every year. How come we do not hear of each of them? It is because they come differently in terms of their destructive power. There are six categories of tornadoes, scaled from F0 up to F5, and is measured with a scale called The Fujita Tornado Damage Scale. Here are the descriptions, in terms of the damage it does:

F0—LIGHT: 

These come as strong winds, with little damage to roofs that are poorly maintained. These winds can displace light-weight objects such as trash cans. They occur very often, making up about 60% of the total number of tornadoes in the year.

F1—MODERATE:

This makes up about 28% of the total number of tornadoes. They cause minor damage to the landscape, young trees, building roofs, and break windows. They can displace heavier objects.

F2—CONSIDERABLE: 

This makes up about 9% of the total number. They break tree branches and bend trees. They cause considerable damage to property as a result of airborne debris. They can move and displace a garden shed with poor foundations.

F3— SEVERE:

These can uproot trees and break the walls of buildings. They can rip off roofs and cause severe damage. This makes up about 3% of the total number of tornadoes, and their destruction usually makes it to the news on TV.

F4—DEVASTATING:

These are pretty destructive, as small cars are blown over and displaced. Well constructed homes are broken, trees are uprooted and blown away. They carry heavy debris and destroy anything in their path. They make up only about 1%.

F5 d—INCREDIBLE:

This makes up less than 1% in number. They are so powerful that they flatten pretty much any structure in its path. Mature trees are left with no branches, others are uprooted and blown away, and automobiles are significantly blown away and displaced.

After a while, the funnel shape of the tornado thins out as it reaches the end of its life, looking like a rope. This is called the rope stage.