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Hurricane Katrina approaches New Orleans
After entering the Gulf of Mexico, Katrina intensified into a large, powerful Category 5 storm as it turned north towards the north-central Gulf coast. Katrina came ashore as a powerful Category 4 storm over southeastern Louisiana and southern Mississippi, causing catastrophic damage and numerous fatalities. The orbiting GOES-12 satellite took the above image of Hurricane Katrina August 28, 2005.
Hurricanes are huge swirling storms with cloud systems typically larger than a state. Tropical cyclones, called hurricanes in Earth's Western Hemisphere and typhoons in the Eastern Hemisphere, get their immense energy from warm evaporated ocean water. As this water vapor cools and condenses, it heats the air, lowers pressure and hence causes cooler air to come swooshing in. Winds can reach over 250 kilometers per hour and become very dangerous. Much remains unknown about cyclones, including how they are formed and the exact path they will take.