Cyclone

A cyclone is a large-scale air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above.

Tropical cyclones form only over warm ocean waters near the equator.

• Warm, moist air over the ocean rises upward from near the surface. As this air moves up and away from the ocean surface, it leaves less air near the surface. So basically as the warm air rises, it causes an area of lower air pressure below.

• Air from surrounding areas with higher air pressure pushes into the low pressure area. Then this new “cool” air becomes warm and moist and rises, too. And the cycle continues…

• As the warmed, moist air rises and cools, the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the ocean surface.

• As the storm system rotates faster and faster, an eye forms in the center. It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye.

When the winds in the rotating storm reach 39 mph (63 kmph), the storm is called a “tropical storm”. And when the wind speeds reach 74 mph (119 kmph), the storm is officially a “tropical cyclone” or hurricane. Tropical cyclones usually weaken when they hit land. However, they often move far inland, dumping many centimeters of rain and causing lots of wind damage before they die out completely.

The criteria below has been formulated by the Indian Meteorological Department (IMD), which classifies the low pressure systems in the Bay of Bengal and the Arabian Sea on the basis of capacity to damage, which is adopted by the World Meteorological Organization (WMO).

• Tropical cyclones trigger serious rainfall and landslides. They cause serious damage to towns and villages. Also, they destroy coastal companies, such as shipyards and oil wells.

• They trigger a lot of crop damage and destroy plenty of forests.

• They are disturbing the entire civic lives, particularly when they kill electricity and telephone lines.

• Torrential rains often accompany these cyclones, which trigger flooding.

• Not only do they cause a lot of damage to assets, but also to people’s lives.

All these problems impact the economy of the nation too.

From 1980 to 2018 tropical cyclones were responsible for nearly half of all natural disaster losses worldwide, with damage amounting to an aggregate of USD 2111 billion.

• The foremost characteristic is that Tropical Cyclones are the most violent, and most disastrous of all the atmospheric disturbances.

• The average speed is 120 kmph. Although it may vary from 32 kmph to 200 kmph or more. At times it reaches 400 kmph also.

• The pressure at the center is extremely low. The winds from the surrounding area are drawn towards this low-pressure core called the "eye" of the cyclone.

• On landfall, their velocity decreases due to friction, and as the source of energy is cut off, they dissipate soon.

• The movement of tropical cyclones is affected by the prevailing wind system. Normally they move from east to west under the influence of trade winds.

• They are seasonal in nature and occur during a specific period of the year only.

The East coast is more prone as compared to the West coast. The most affected states are Odisha, West Bengal, Andhra Pradesh, Tamil Nadu, Kerala, Maharashtra and Gujarat.

What to do before the cyclone and when warning is received

1. Check the house, secure loose tiles and repair doors and windows.

2. Remove or secure loose lamps, trees etc.

3. Keep dry non-perishable food and electric bulbs ready for emergencies.

4. Listen to All India Radio for forecasts and warnings

5. Evacuate when the Government authorities instruct after closing the doors and windows securely. Don't stay back.

6. Carry extra food, stove, drinking water, torch, battery, transistor, and essential medicine while evacuating.

7. Switch off the main switch of your house before evacuation.

What to do during cyclone

1. All family members remain close.

2. Switch of all electrical appliances.

3. Stay in an empty room and Do not go out.

4. Movable items should be kept securely tied.

What to do after the cyclone

1. Those who shifted to the cyclone centre must remain there till instructions are received.

2. Strictly avoid loose electrical wires after the cyclone.

3. Beware of snakes and other animals immediately after the cyclone.

4. Clear debris and carcasses from/near the premise after the cyclone.

Union-

The Ministry of Home affairs plays a significant role in coordinating the management of flood and cyclones except for drought. Drought is managed by the Ministry of Agriculture.

State-

The States have been provided with a relief manual called ‘State Relief Code’ and State Contingency plan. These manuals guide the state Government to face the disaster like flood and cyclone

District-

The Disaster Management Committee at the district level which is headed by the district magistrate takes the decisions during flood and cyclone and seeks the help of disaster management teams like Police, doctors, Fire service, etc.

Tauktae was a disastrous tropical cyclone in the Arabian Sea that became the strongest tropical cyclone to make landfall in the Indian state of Gujarat since 1998 and one of the strongest tropical cyclones to ever affect the west coast of India. Tauktae originated from a tropical disturbance, which was first monitored by the India Meteorological Department on May 13. Early on May 17, Tauktae intensified into an extremely severe cyclonic storm, reaching its peak intensity soon afterward. Later that same day, Tauktae underwent an eyewall replacement cycle and weakened, before restrengthening as it neared the coast of Gujarat, making landfall soon afterward. On May 19, Tauktae weakened into a well-marked low-pressure area.