Hurricanes are tropical cyclones. When a tropical cyclone's sustained winds reach 39 to 73 mph (63 to 118 km/h), it is considered a tropical storm and it gets a name from a list put out by the World Meteorological Organization. Once those sustained winds reach 74 to 95 mph (119 to 153 km/h), that storm becomes a Category 1 hurricane. According to the Saffir-Simpson scale, here are the sustained winds linked to categories 2 through 5 hurricanes:
- Category 2: 96 to 110 mph (154 to 177 km/h)
- Category 3: 111 to 129 mph (178 to 208 km/h)
- Category 4: 130 to 156 mph (209 to 251 km/h)
- Category 5: 157 mph or higher (252 km/h or higher)
Hurricanes are the most violent storms on Earth, according to NASA. At heart, hurricanes are fueled by just two ingredients: heat and water. Hurricanes are seeded over the warm waters above the equator, where the air above the ocean's surface takes in heat and moisture. As the hot air rises, it leaves a lower pressure region below it. This process repeats as air from higher pressure areas moves into the lower pressure area, heats up, and rises, in turn, producing swirls in the air, according to NASA. Once this hot air gets high enough into the atmosphere, it cools off and condenses into clouds. Now, the growing, swirling vortex of air and clouds grows and grows and can become a thunderstorm.
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