And their effect on the built environment They are known as Hurricanes in the Caribbean, Typhoons in the China Sea, Cyclones in the Indian Ocean and most commonly called Tropical Cyclones. 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 air is sucked in below. The warm air gains moisture and starts producing thunderclouds. Spinning in a clockwi