Always formed in the waters of the oceans, you hurricanes they are cyclones tropical, as well as typhoons. The origin of these meteorological phenomena is the same as rain. However, hurricanes can last up to a week and, when they reach the coast, they cause great destruction, with winds exceeding 200 km/h.
The big difference between typhoons and hurricanes are the places where they are formed. The first is generally formed in the Northwest Pacific Ocean and usually reaches South Asia. Hurricanes can form in the North Atlantic, Northeast Pacific and South Pacific and can affect the Americas, especially the North.
To understand how these phenomena occur, it is necessary to understand the origin of rains, which takes place in two stages: first, the vaporization of water; then, the condensation of this vapor, falling again in the form of water. When this occurs in warm ocean waters, with temperatures above 27ºC, hurricanes can be formed.
See too: how the names of hurricanes and typhoons are chosen
In general, this water heating takes place in tropical areas, that is, between the Tropics of Cancer and Capricorn, therefore, the phenomenon is classified as a tropical cyclone. At these latitudes, the water turns into steam and rises heated from the ocean to the clouds, leaving the atmospheric region, close to the sea surface, with a lower pressure. This causes cold air, which has a higher pressure, to invade the space vacated by the steam that has risen. As a result, the cold air also heats up and rises in circular motions.
In the upper atmosphere, the hot air cools down and turns into a cloud, forming a system of clouds and moving air. The heat from the ocean and evaporating water causes the winds to accelerate more and more, forming a current of air that moves in a circular motion, giving the hurricane a cone-like appearance.
Circular movement of the air stream gives rise to the hurricane
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The curious thing is that, despite the speed at which the winds circulate, the “eye of the hurricane” is relatively calm, an average of 30 km/h. The reason for this is quite simple: with circular winds, the speed is only on the walls of the tornado, leaving a clear passage in the center.
Another interesting fact is that, in the Southern Hemisphere, hurricanes move clockwise; but in the Northern Hemisphere, counterclockwise. This fact occurs because of the movement of air that is concentrated in different directions.
Devastation
Destruction begins when winds sweep across the coast. Hurricanes tend to destroy buildings, drag cars and uproot trees, but it all depends on the speed of the winds. The Saffir-Simpson scale classifies hurricanes into five categories. Category 1 groups hurricanes with winds from 118 km/h to 153 km/h; Category 5, on the other hand, includes hurricanes with winds above 250 km/h.
Many hurricanes lose strength when reaching areas with cold waters and do not come into contact with the continent. Those who find the coast tend to lose speed as they move inland.
Many hurricanes or typhoons they devastated cities and rural areas, leaving a trail of destruction and despair in their wake. Among the best known is Irma, in 2017, Matthew, in 2016, Patricia, in 2015, the hayan, in 2013, Katrina and Wilma, in 2005, Sandy, in 2002, and Audrey, in 1957, to name a few.
Despite being common in Central and North America, hurricanes have already hit some regions of South America, such as Catarina, which, in 2004, caused destruction in southern Brazil.
Tornado and Hurricane
Remember that hurricane and tornado are different phenomena, as the first originates in the ocean and the second, generally, in the land. Also, a tornado can be seen entirely with the naked eye, whereas hurricanes are too big for that.
by Rafael Batista
Brazil School Team