Part of: Prelims and GS – III – Disaster management
Context Recently, Hurricane Ida made landfall in Louisiana, US. It is an extremely dangerous Category 4 storm and one of the most powerful storms ever to hit the US.
What are Hurricanes?
- Hurricanes are the biggest and most violent storms on the planet.
- Tropical cyclones or hurricanes use warm, moist air as fuel, and therefore form over warm Equatorial water.
Mechanism of the hurricanes
- When the warm, moist air rises upward from the surface of the ocean, it creates an area of low air pressure below.
- When this happens, the air from the surrounding areas rushes to fill this place, eventually rising when it becomes warm and moist too.
- An eye forms in the centre. It is the calmest part of the cyclone. Before the wind reaches the centre it gets warmed up and rises upwards.
- When the warm air rises and cools off, the moisture forms clouds. This system of clouds and winds continues to grow and spin.
- This disturbance is fuelled by the ocean’s heat and the water that evaporates from its surface.
- Such storm systems rotate faster and faster.
- Storms that form towards the north of the equator rotate counterclockwise, while those that form to the south spin clockwise because of the rotation of the Earth.
Names in Different Regions of the World:
- Typhoons: Tropical cyclones are known as Typhoons in the China Sea and Pacific Ocean.
- Hurricanes: In the West Indian islands in the Caribbean Sea and Atlantic Ocean.
- Willy-willies: In north-western Australia
- Tropical Cyclones: In the Indian Ocean Region.
Categorization of Hurricanes:
- Hurricanes are categorized on the Saffir-Simpson Hurricane Wind Scale, which rates them on a scale of 1 to 5 based on wind speed.
- Hurricanes that reach category three or higher are classified as major hurricanes.