What are cyclones ?
To put it simply, Cyclones are high intensity storms that are formed in the sea, can last for days and have trajectories ranging over large distances, often multiple countries. As they move, they generate high speed winds (sometimes upto 300kmph) and heavy rainfall.
In different parts of the world , cyclonic storms are known by different names – Hurricanes in North America and Typhoons in Philippines. But they all refer to the same phenomenon
How are cyclones formed ?
You must wonder why do we never hear about Cyclones in Delhi in rainy season! Well, such powerful storms are formed only when certain conditions are met , like –
- Tropical climate
- Large body of hot water
- Sustained wind system
The tropical region lies between the Tropic of Cancer and the Tropic of Capricorn. Being closer to Equator, this region receives direct sunlight and temperature here is higher as compared to other parts of Earth. This high temperature heats up large water bodies like oceans and water vapour begins to rise up through evaporation. A sustained wind system then comes into action and takes these vapours higher up in atmosphere where they condense to form clouds. Gradually this system begins to spiral around a center called the eye of the cyclone. Notice how these conditions came together for Cyclone Amphan. It was summers in North Hemisphere in May and the Bay of Bengal was heating up. Added to this there is continuous wind blowing over this sea.
The Landfall
This system then moves across the sea becoming stronger. Some storms that don’t accumulate enough moisture dissipate in the sea itself. The rest move from low pressure region to high pressure region towards land. The event of a cyclone hitting land is called landfall. The coastal point at which landfall happens is the worst affected region because beyond this the cyclone runs out of moisture (without the water body) and gradually weakens. However, the accumulated clouds and winds still cause a lot of destruction.
Cyclone Prediction and Preparedness
Much like earthquakes, we can’t stop cyclones. Luckily, since they intensify for days in seas, weather scientists monitor them through satellites and try to predict their path accurately. Timely warnings are essential so that fishermen can be advised to stay away from seas, people can be moved from flood prone low-lying areas. Due to strong winds flights, electric wires and old buildings are especially vulnerable. Cyclone prone states like Odisha have built shelters where people can take refuge during landfall. All this minimizes loss of life and livelihood.
So who called it Nisarga?!
Just like people and pets it is easier to identify a storm if it has a name. By this time we know that the cyclone in an ocean basin can impact any or multiple nearby countries (like India, Pakistan or India, Bangladesh) . So every year each country sends cyclone names to form a central list. As and when storms are formed , names are picked up from this list. The name Nisarga was from Bangladesh’s list.
Where else in the world?
Now, with all this information about cyclones, open up a world map and try to see which other parts of the world are prone to it!