Hurricanes

Natural Disasters - Hurricanes Hurricane is the phenomenon for a cyclonic storm system that forms over the oceans. It is caused by evaporated water that comes off of the ocean and becomes a storm. The Coriolis Effect causes the storms to spin, and a hurricane is declared when this spinning mass of storms attains a wind speed greater than 74 mph. Hurricane is used for these phenomena in the Atlantic Ocean, tropical cyclone in the Indian, and 'typhoon in the eastern Pacific. Hurricanes have different names in different areas, they are also known as typhoons, cyclones, and cyclonic storms. The word Typhoon is derived from the Chinese word 大風 which means Great Wind. Tropical cyclones are usually formed in seven main basins including: North Atlantic Basin Western North Pacific Ocean Eastern North Pacific Ocean South Western Pacific Ocean Northern Indian Ocean Southeastern Indian Ocean Southwestern Indian Ocean The Eye of a cyclone is an area of sinking air at the center of circulation. Weather in the eye is normally calm and free of clouds. The eye is normally circular in shape and can range from 8km to 200km in diameter. Examples: Bhola cyclone (1970) Wilma devastated parts of Florida (2005) Great Hurricane of 1780 (Martinique, St. Eustatius and Barbados) Structure Hurricanes form when the energy released by the condensation of moisture in rising air causes a positive feedback loop. The air heats up, rising further, which leads to more condensation. The air flowing out of the top of this “chimney” drops towards the ground, forming powerful winds. Structure of a hurricane Gallery Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004. The aftermath of Hurricane Katrina in Gulfport, Mississippi. Katrina was the most costly tropical cyclone in United States history.