Cyclone Nivar: All about tropical cyclones

This article has been created based on The Hindu Editorials:  Storm warnings: On weather forecast and Cyclone Nivar appeared on 27th November 2020.

Introduction

According to the India Meteorological Department (IMD), Cyclone Nivar, which crossed the TN coast as a very severe cyclonic storm with wind speeds of 120 kmph and rain-filled, further weakened as it moved inland.

The storm system is likely to move northwestwards and weaken into low pressure. Subsequently, Cyclone Nivar weakened into a cyclonic storm and further into a deep depression, centered about 50 km west-southwest of Tirupati.

Cyclone Nivar is the second cyclone to form over the Bay of Bengal this year after Super Cyclone Amphan.

Read about Amphan and few basics in ForumIAS blog by clicking here

What are Tropical Cyclones?

They are violent storms that originate over oceans in tropical areas and move over to the coastal areas bringing about large-scale destruction caused by violent winds, very heavy rainfall and storm surges.

• Conditions: The conditions favourable for the formation and intensification of tropical cyclones are:
  • Large sea surface with temperature higher than 27° C;
  • Presence of the Coriolis force enough to create a cyclonic vortex
  • Small variations in the vertical wind speed;
  • A pre-existing weak low-pressure area or low-level-cyclonic circulation is must for cyclone formation in tropics
  • Upper divergence above the sea level system.

Vulnerability of India to Cyclone:

• Indian sub-continent is the worst affected region of the world, having a coast line of 7516 kms. (5400 kms along the mainland, 132 kms in Lakshadweep and 1900 kms in Andaman and Nicobar Islands) is exposed to nearly 10% of the world’s Tropical Cyclones.
• 40% of the total population lives within 100 km of coastline.
• Four States (Andhra Pradesh, Odisha, Tamil Nadu, and West Bengal) and one UT (Pondicherry) on the East Coast and One State (Gujarat) on the West Coast are more vulnerable to cyclone disasters

Benefits of Tropical Cyclones:

Although Tropical cyclones are known for the destruction they cause, when they strike, they also bestow certain benefits to the climatic conditions of that area such as

• Relieve drought conditions: By bringing rain to the coastal areas, cyclones relieve the drought like conditions in the surrounding areas.
• Maintain equilibrium in the Earth’s troposphere: They Carry heat and energy away from the tropics towards temperate latitudes, thus helps in maintaining equilibrium of the troposphere.
• Cyclones help in maintaining a relatively stable and warm temperature worldwide.

Causes of destruction caused by Cyclones:

There are three elements associated with cyclones that cause destruction during its occurrence. These are:

• Strong Gusts/Squall:
  • These are very strong winds that accompany a cyclonic storm damages installation, dwellings, communications systems, trees, resulting in loss of life and property.

• Torrential rains and inland flooding: Torrential rainfall (more than 30 cm/hour) associated with cyclones is another major cause of damages.
  • Unabated rain gives rise to unprecedented floods.
  • Rain is a serious problem for the people which become shelter less due to cyclone.
  • Heavy rainfall from a cyclone is usually spread over wide area and cause large scale soil erosion and weakening of embankments.
• Storm Surge: It can be defined as an abnormal rise of sea level near the coast caused by a severe tropical cyclone;
  • Seawater inundates low-lying areas of coastal regions drowning human beings and life stock, causes eroding beaches and embankments, destroys vegetation, and leads to a reduction of soil fertility.
• Apart from these Cyclones also create destructions such as
  • Sudden Change in Regional climate: The ability of cyclone to bring in warmer air is high. So, the elderly and children in those areas have a high vulnerability to develop heat-related problems such as heat strokes.
  • Loss of Livelihood: The majority of the coastal people generally depend on fishing which is completely halted by cyclones.
  • Loss of economy: The economic loss is in multifront from infrastructure loss, relief packages to people, etc.

Challenges in Cyclones Management:

• Bare minimum Technology: At the terminal-end generally lacks the equipment and communication back-up to deal with the situation effectively.
• Lack of grass root level participation: There is a wider awareness gap is there between disaster management from people’s end.
• Multiple agencies: The IMD issues meteorological or weather forecasts while the Central Water Commission (CWC) issues flood forecasts at various river points. But cyclones bring the combination of problems. Before the integration of data people on the ground lost the “golden time”.
• Low data: The government has not measured the peak flows in the rivers and canals to plan remedies and also not documented data on annual flooding patterns.
• Absence of land use norms has spawned an amorphous housing sector characterized by inflated, speculative prices but no foundation of civic infrastructure.
• Poor Urban planning: Many Indian cities lacks poor urban planning which is highlighted by floods in Chennai and Mumbai.
• Climate Change: There are many proven records that exist between the link between the higher frequency of disaster and climate change.

Government Initiatives:

• Government is carrying out a National Cyclone Risk Mitigation Project (NCRMP) with the help of the World Bank for upgrade cyclone forecasting, tracking and warning systems in India
• Government is also implementing Integrated Coastal Zone Management Project (ICZMP) to improve national capacity for the implementation of comprehensive coastal management in India.
• Government also separated Structural(includes construction) and non-structural measures for effective disaster management of cyclones
• Solutions:
• The government should consider the NDMA Guidelines for the management of cyclones:
• Ensemble Warning System(EWS): Establish EWS involving observations, predictions, warnings, and customized local level advice for decision-makers (national, state, district level) to manage the impact of the cyclone (Read more about EWS)
• Commissioning of Aircraft Probing of Cyclone (APC): Guidelines calls for the combination of manned and Unmanned Aerial Vehicles (UAV) for critical observational data gaps.
• Cyclone Disaster Management Information System (CDMIS): Establishing a comprehensive department for coverage of all management information and provide online services to the departments of Disaster management.
• Specifying the roles and responsibilities in institutionalizing Cyclone risk mitigation with Developmental planning.
• Community Based Disaster Management (CBDM): Guidelines asked to launch such activities in all villages of the 84 districts vulnerable to cyclones.

Way forward:

• With the adverse Climate Change risks posted by IPCC reports the only option for India is to better preparedness for the disaster with better urban planning, community awareness, etc.