Cyclone: Amphan

A Cyclone is a large scale air mass that rotates around a strong center of low atmospheric pressure. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure. The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale.

    

  Cyclogenesis is the process of cyclone formation. Tropical cyclogenesis describes the process of the development of tropical cyclones. Tropical cyclones form due to latent heat driven by significant thunderstorm activity and are warm core. Cyclones can transition between extratropical, subtropical, and tropical phases. There are six main requirements for tropical cyclogenesis:

   # sufficiently warm sea surface temperatures,

   # atmospheric instability,

  # high humidity in the lower to middle levels of the troposphere,

  # enough Coriolis force to develop a low-pressure center,

  # a preexisting low-level focus or disturbance,

  # low vertical wind shear.

       Mesocyclones form as warm core cyclones over land and can lead to tornado formation. Waterspouts can also form from mesocyclones, but more often develop from environments of high instability and low vertical wind shear.

Cyclone Amphan :

      Super Cyclonic Storm Amphan was a very powerful and deadly tropical cyclone that caused widespread damage over East India and Bangladesh in May 2020. It was the strongest tropical cyclone to strike the Ganges Delta, and the first super cyclonic storm to occur in the Bay of Bengal since the 1999 Odisha cyclone. Causing over US$13 billion of damage, Amphan is also the costliest cyclone ever recorded in the North Indian Ocean, surpassing the record held by Cyclone Nargis of 2008.

       Amphan originated from a low-pressure area persisting a couple hundred miles (300 km) east of Colombo, Sri Lanka, on 13 May 2020. Tracking northeastward, the disturbance organized over exceptionally warm sea surface temperatures; the Joint Typhoon Warning Center (JTWC) upgraded the system to a tropical depression on 15 May while the Indian Meteorological Department (IMD) followed suit the following day. On 17 May, Amphan underwent rapid intensification and became an extremely severe cyclonic storm within 12 hours.

       Coastal areas in Odisha—as well as Kolkata, Hooghly, Howrah, East Midnapur, North 24 Parganas, and South 24 Parganas in West Bengal—were affected by the cyclone. It also caused significant destruction in Bangladesh.

Impact-

           West Bengal, the epicenter of the cyclone's landfall, saw the most widespread damage from Amphan. The storm was considered the strongest to hit the region in over a decade.

Economic Impacts:

            This section analyzed the economic impacts of the affected households in the aftermath of the cyclone Amphan. A comparison was made between migrant and non-migrant households with regard to their economic conditions in terms of impacts on occupation, income, and loan status.

          In Kolkata, damaging winds up to 133 km/h (83 mph) overturned vehicles and snapped trees.  North 24 Parganas has also faced damage of several thousands of houses. Thousands of mud homes were damaged in the neighboring Hooghly district. At least 80 people died in West Bengal, of which 19 in Kolkata;  most of the fatalities were due to electrocution or the collapse of homes. Hundreds of homes were wrecked in South 24 Parganas and breached embankments led to the flooding of villages and swaths of cropland. The damage there was more extensive than in Cyclone Aila in 2009. Across West Bengal, 88,000 hectares (217,000 acres) of rice paddies and 200,000 hectares (500,000 acres) of vegetable and sesame crops have been damaged. Kolkata alone has lost 5000 trees in the cyclone. The government estimated the losses across the state to be ₹1 trillion (US$13.2 billion).

      Neighboring Odisha saw significant effects, with wind gusts reaching 106 km/h (66 mph) and rainfall up to 197.1 mm (7.76 in) in Paradip. 65 electrical substations were affected, leaving 1.9 million without power. Three people died in Odisha, one due to drowning, and the other two from collapsed objects.

Social Impacts:

         This section discussed the social impacts of Cyclone Aila on the migrant and non-migrant households with regard to their housing condition, water and sanitation issues, food consumption pattern, farmland holding, and source of fuel based on the findings from the field survey.

         As West Bengal and Odisha is an agriculture-based state, it is evident that around 36% of households were engaged in agriculture including forestry, animal husbandry, and fisheries. People living in coastal areas are mostly small and marginal farmers who mostly relied on rain-fed agriculture. Climatic events affect the productivity of agricultural land; thus, smallholders, marginal farmers are affected more.

         The loss and damage as a result of the cyclone Amphan were so severe that the government, national and international donor agencies provided cash grants and other types of humanitarian support to affected communities to assist them in the recovery process. However, relief efforts were not adequate to recover from their losses, so vulnerable households had to borrow from formal and informal institutions.

Migration:

The factors that induced migration after the cyclone was also analyzed. Using the logistic regression model, the results show that factors like households who were functionally landless; more interested in migration. The analysis depicted that the type of house was also positively correlated with migration. Households who belong to better housing (semi-pacca or pacca) infrastructure were more likely to migrate.

        On 22 May, Prime Minister Narendra Modi conducted an aerial survey over Kolkata, along with chief minister Mamata Banerjee. Modi announced an ₹10 billion (US$132 million) immediate relief for West Bengal and an ₹5 billion (US$66.2 million) relief for Odisha. In advance, Modi announced that ₹200,000 (US$2,650) would be provided to the next of kin of people who died during the storm, and ₹50,000 (US$660) would be given to each injured person.