INSTANT EXPERT: TORNADOES
Learn the facts, reap the whirlwind.
A full-fledged tornado is the most forceful and scary phenomenon in our atmosphere. It is an intensive, rotating air column with the strongest wind on Earth, which stretches from a powerful thundercloud towards Earth’s surface. Where the tornado reaches the ground, it leaves a path of concentrated destruction.
Tornadoes can occur anywhere on Earth except in the coldest regions, but luckily, not many places in the world have the full set of ingredients required to produce the most forceful tornadoes. Those you will find in either Midwestern USA or Eastern India and Bangladesh, where periodic atmospheric conditions cause heavy showers. That could be the first step towards a tornado.
A tornado belongs to the family of whirlwinds, and is simply rotating air. The term covers anything from the rather innocent dust devils with an extent of a few metres, which are caused by local warming of the ground, to major, rotating low-pressure systems with an extent of up to thousands of km. Waterspouts and willy-willies are essentially small tornadoes. A tornado is the most powerful of all whirlwinds in the world.
The formation principles of all of them are about the same. Instability in the atmosphere causes intense thunderstorms. Around and inside the thunderstorm, the whirls are produced due to a series of processes, of which the wind change with altitude and powerful lift are the central ones, which provide the phenomenon with its vigorous force.
In regions with intense tornado activity such as the United States, a constant eye is kept on weather situations which could produce tornadoes, and experts try to predict the situation as well as possible to allow for prior warning. However, this is difficult, even though the experts are getting slightly better at it all the time due to more sophisticated tools. It is difficult to predict the development of a thundercloud and whether it is going to develop into a tornado. So, in regions with risk of tornadoes, it is necessary to consider safety, and many people have built special shelters for their families.
The rotating wind of a tornado is the most forceful on Earth. It can reach a speed of about 500 km/h, twice as much as the most forceful tropical hurricanes.