The Tropical Cyclone / Hurricane season begins “officially” on May 15 for the Pacific Ocean. According to the World Meteorological Organization (WMO), the names designated for this year are: Amanda, Boris, Cristina, Douglas, Elida, Fausto, Genevieve, Hernán, Iselle, Julio, Karina, Lowell, Marie, Norbert, Odalys, Polo, Rachel, Simón, Trudy, Vance, Winnie, Xavier, Yolanda, Zeke.
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In the case of the Atlantic, the season begins “officially” June 1. The names that will be used according to WMO are: Arthur, Bertha, Cristobal, Dolly, Edouard, Fay, Gonzalo, Hanna, Isaías, Josephine, Kyle, Laura, Marco, Nana, Omar, Paulette, René, Sally, Teddy, Vicky Wilfred
For both the Pacific and the Atlantic, the season ends until November 30 with the peak in September (statistically).
A tropical cyclone is an organized system of clouds and storms that originates over tropical or subtropical waters and has a closed circulation center in the lower levels of the atmosphere.
Tropical cyclones rotate around a low pressure center counterclockwise in the northern hemisphere, in the southern hemisphere they rotate clockwise.
How tropical cyclones form
Tropical cyclones require warm water with temperatures above 27 ° C, this is their main “fuel”.
Warm, humid air over the ocean rises from near the surface.
As the air moves upward – away from the surface – less air remains near the surface, warm air rises causing an area of lower pressure near the ocean.
Air with higher pressure from the surrounding areas fills the low pressure area.
As the warm and humid air continues to rise, the surrounding air enters diagonally through the coriolis effect, which rotates the system. When warm, humid air rises and cools, the water in the air forms clouds. The entire cloud + air system rotates and grows, fed by the heat of the ocean, and the water that evaporates from the surface grows more and more if the water is warmer and the wind at height is minimal (little wind at height favors the development of cyclones).
As the storm system rotates faster, an eye forms in the center. In the eye, everything is very calm and clear, with very low air pressure.
The Tropical cyclones are classified into three stages according to the speed of its winds:
Tropical depression: when its winds are less than 63 km / h.
Tropical storm: winds between 63 km / h and 118 km / h.
Hurricane: winds with a speed greater than 118 km / h and they are classified according to the speed of their winds using the Saffir – Simpson scale:
Category 1 – 119-153 km / h
Category 2 – 154-177 km / h
Category 3 (major hurricane) – 178-208 km / h
Category 4 (major hurricane) – 209-251 km / h
Category 5 (major hurricane) – 252 km / h or higher
TROPICAL CYCLONE is the generic term that ranges from tropical depression to a category 5 hurricane.
The most important dangers associated with tropical cyclones are:
Storm surges: sea levels rise and flood coastal areas.
Strong winds: They can exceed 300 km / h by throwing loose objects at high speed, knocking down trees, branches, signs, and knocking down roofs.
Intense rains: it is not necessary for an intense hurricane to occur, a tropical depression can leave in a few hours the equivalent of rain in months, causing floods, overflowing rivers and landslides of unstable slopes.
Mudslides: slopes of hills or mountains can come off due to the intense rains that saturated the soils with water. Deforestation makes many of these slopes prone to sliding and causing severe damage to the population.