The word tornado comes from the Spanish word tornado, which means storm. The tornado has dimensions and duration much smaller than that of a hurricane. However, this phenomenon is capable of promoting great destruction wherever it goes, such as, for example, what hit Shaturia, Blagladesh, in 1989, killing approximately 1,300 people and leaving another 50,000 homeless.
Tornadoes are atmospheric eddies characterized by a spiral, in the form of a wind funnel, that revolves around a center of low atmospheric pressure; they are produced by a single convective storm. Normally, its formation takes place in the late afternoon, as during this period the atmosphere presents greater instability, it contains an average of 100 meters in length, and, unlike hurricanes, its duration is few minutes.
Tornadoes are typically continental phenomena, formed through the arrival of cold fronts in regions where the air is more hot and unstable, favoring the triggering of a storm, which, in turn, drives the formation of this type of Hurricane.
Because they present favorable physical aspects for the occurrence of tornadoes, in some countries this phenomenon occurs more regularly, among them are: the United States, Uruguay, Argentina and the south of the Brazil.
Tornado formation process:
1 - The cold air mass forms a “cap” over the hot air mass close to the ground, preventing the formation of clouds. With the entrance of a cold front or by excessive heating of the air strip close to the ground, the hot air breaks the lid and invades the cold air mass.
2 - The hot air rises and expands at a speed that can reach 250 KM/h. Instability in the atmosphere can cause the expansion movement to spiral.
3 - Condensed moisture falls as rain. With evaporation, the tornado forms below the “lid”, in an area where there is no rain. Unlike hurricanes, tornadoes are compact and short lived.
By Wagner de Cerqueira and Francisco
Graduated in Geography
