And their effect on the built environment They are known as Hurricanes in the Caribbean, Typhoons in the China Sea, in the Indian Ocean and most commonly called Tropical . You can call them what you want but they all have one thing in common: they are extremely destructive when they hit cities and towns. A cyclone is a huge mass of air moving in a spiral with winds that can reach up to 250 km/h. A cyclone starts off in the sea where the winds are calm and the water temperature is at least 240. Warm air pushes upwards at a fast rate while cold ....