Who Named ‘Dana’ and How Does a Cyclone Develop?

Sandipan Talukdar

The predicted tribulation in the form of cyclone ‘Dana’ may have abated, as IMD (Indian Meteorological Department) says in its latest bulletin issued at 11.30 AM today that the landfall process has been completed. The landfall took place at midnight between 1.30 AM to 3.30 AM at the Odisha coast between Bhitarkanika in Kendrapara district and Dhamra in Bhadrak. The cyclonic system is weakening gradually and by 5.30 PM today it will become a depression, meaning no storm at that moment.

During landfall, the severe cyclone stormed the Odisha coast with wind having speed between 100-110 kmph and gusting upto 120 kmph. As claimed by Odisha government it could achieve the zero casualty goal which it emphasized is due to the early preparedness measures of the government. The train communication that disrupted are resuming slowly.

Who Named ‘Dana’?

The name Dana was given by the country Qatar, which in Arabic means ‘Generosity’. But how does a cyclone gets is name? Well, it’s a well formulated process by the WMO (World Meteorological Organization). The names are chosen by a group of nations which are part of the WMO including India, Bangladesh, Sri Lanka, Maldives, Myanmar, Oman, Pakistan, and Thailand. This group started tnaming the cyclones in the region back in 2000.

However, in 2018, the WMO added few other countries to the group which are Iran, Qatar, Saudi Arabia and the UAE (United Arab Emirates) and Yemen. Thus the total number of countries in the system is 13. The countries send names to a panel of WMO which later finalizes the list of the cyclones and their names.

Cyclone naming depends on some important criteria like political and cultural neutrality, how easy is it to pronounce and with a limit of eight letters. All the 13 member countries suggest 13 names each and the WMO compile a list. After all the names are used, the next cycle begins with new names from each member nations.

The recent cyclone that bears an Indian name was ‘Vayu’ that hit India’s western coast in Gujarat in June 2019. The intensity of Vayu was more severe than Dana with wind speed of 170 kmph.

How Does a Cyclone Form?

Remember the place for the genesis of a cyclone is the ocean or the sea. It forms there, gathers tremendous energy and moves towards land (coast for example) where it creates the havoc and after encountering land it loses its energy. The time that a cyclone remains in the land, it shows its prowess.

Warm and moist air is the fuel of a cyclone and the best place is over the ocean. When the air over an ocean gets sufficiently warmed, it moves up away from the ocean surface leaving less air near the surface and this causes low-pressure area below. This is what is named as ‘depression’.

Development of such a low-pressure area leads to rushing of air from surrounding areas with a high pressure (cool air) level. This results in warming of the cool air getting warmer and moist and eventually this moves up. This begins a cycle where warm air moves away from the ocean surface causing a low pressure area and cool air from surrounding area filling up the space. The cool air again warms and moves up.The warm and moist air that moves upward from the ocean surface gets cooled and as a result of this cooling the water (moisture) in the air forms clouds. The entire system comprising cloud and wind spin grows further with the constant supply of fuel in the form of warm ocean surface.

The system starts rotating and this rotation develops an eye at the centre, which is known as the eye of the storm. However, the eye of the storm appears to be calm due to low air pressure.

The cyclone system when encounters the land, which is the Odisha coastal areas in case of Dana, it gets cut off from the fuel supply, that is hot and moist air from the ocean and it gradually weakens. Nonetheless, during the time the cyclone spends over the land it devastates with all its prowess till it weakens. The cloud that a cyclone carries inundates a large expanse of areas consistently for some time.

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