Tropical Cyclone Nivar – Effects and Facts for UPSC

Introduction: The fourth cyclonic storm in the Bay of Bengal region in 2020 was Cyclone Nivar. Preceding Nivar were three other cyclonic storms: Amphan affecting West Bengal and Bangladesh, Nisarg impacting Maharashtra and the Arabian Sea, and Gati in Somalia. On November 26, 2020, Cyclone Nivar made landfall near Karaikal in Puducherry during the early hours.

The formation of Cyclone Nivar can be traced back to a low-pressure area in the Bay of Bengal on November 22. Gradually intensifying, it developed into a severe cyclonic storm by November 24, 2020. The impact of Nivar was substantial, bringing extremely heavy rainfall and violent winds with speeds reaching approximately 120 kmph to the affected areas of Tamil Nadu, Andhra Pradesh, and Puducherry.

Why is it called Cyclone Nivar?

• Iran named the cyclone Nivar in accordance with the guidelines of the World Meteorological Organization (WMO).
• Cyclones in the North Indian Ocean region, which includes those formed in the Arabian Sea and the Bay of Bengal, are named by countries within their respective areas.
• The North Indian Ocean region consists of 13 member countries: Bangladesh, India, Maldives, Myanmar, Oman, Yemen, Pakistan, Sri Lanka, Thailand, Qatar, Saudi Arabia, UAE, and Iran.
• Each of these member countries contributes a list of 13 names, resulting in a total of 169 names for cyclones.
• The names of member countries are arranged alphabetically, and cyclones are named sequentially without repetition.
• The primary goal of assigning common names to cyclones is to aid in identification and prevent confusion.
• Common names for cyclones offer additional benefits, including facilitating media reporting and information dissemination, thereby enhancing preparedness and understanding.

Effects of Cyclone Nivar

1. Cyclonic storm Nivar caused a minimum of four deaths in Tamil Nadu and eight in Andhra Pradesh.
2. Affected areas, including Chennai and Puducherry, experienced exceptionally heavy rainfall, with Chennai recording 31 cm and Puducherry receiving 30 cm, effectively eliminating the rain deficit.
3. Light to moderate rainfall persisted in the affected and neighboring regions for 48 hours.
4. Severe damage was reported in the Prakasam district of Andhra Pradesh, where 2,500 hectares of paddy seedlings were submerged, and 34,000 hectares of standing crops were severely affected.
5. Strong winds of 60-70 kmph uprooted trees, damaged electricity poles, and disrupted communication systems.
6. Continuous rainfall led to flooding in Puducherry, Tamil Nadu, Andhra Pradesh, Chennai, and surrounding areas.
7. The economic impact was significant, with millions of dollars in losses, particularly in the agricultural and electricity sectors, especially in the flooded regions.

Formation of cyclone Nivar

The formation of cyclone Nivar is explained in key points:

• November 22, 2020: A low-pressure area formed over the warm waters of the Bay of Bengal off the Tamil Nadu coast due to rising hot air masses.
• November 23, 2020: Continuous uplift of hot air masses led to the intensification of the low-pressure area, transforming it into a depression.
• November 24, 2020: The depression strengthened further and was officially named Nivar.
• Indian Meteorological Department (IMD) issued warnings about the cyclonic landfall off the coasts of Tamil Nadu, Puducherry, and Sri Lanka.
• November 25, 2020: Nivar reached its peak intensity, being categorized as a severe cyclonic storm by the IMD.
• Early hours of November 26, 2020: Nivar made landfall on the Markkanam coast of Puducherry.
• Nivar, now in the form of a deep depression, returned to the Bay of Bengal and made another landfall on the same day on the Andhra Pradesh coast in the Rayalaseema region.

Early Warning System for Cyclone Nivar

Established in 1990 within the Indian Meteorological Department (IMD) in New Delhi, the Cyclonic Warning Division (CWD) serves as a regional specialized meteorological center with a multilateral approach. Its primary functions include monitoring, predicting, and issuing warning services for tropical cyclones that develop in the North Indian Ocean region.

• Standardization of all components within the Early Warning System (EWS) for tropical cyclones is a key feature outlined in the standard operating procedure for cyclone warnings in India. This initiative aims to enhance the effectiveness of cyclone warnings across the country.
• The Cyclone Warning Department is dedicated to advancing cyclone warning endeavors in India. Its overarching mission is to bolster the connection between the early warning system for cyclones and disaster management, thereby contributing to the overall improvement of cyclone warning activities in the nation.

Important functions of the cyclone warning department are the following:

• Maintaining constant surveillance across the entire North Indian Ocean region.
• Analyzing and processing global meteorological data for prediction and diagnostic purposes.
• Detecting, tracking, and predicting cyclones in both the Bay of Bengal and the Arabian Sea.
• Issuing cyclonic warning bulletins to ensure comprehensive coverage, distributed through All India Radio, Doordarshan, other TV channels, and print media.
• Coordinating with the government and various agencies on all matters related to cyclonic storms.
• Collecting diverse information from state governments and other reliable sources about historical occurrences of cyclonic storms.

Area Cyclonic Warning Centers (ACWCs) / Cyclonic Warning Centers (CWCs)

• India hosts three Area Cyclonic Warning Centers (ACWCs) located in Kolkata, Mumbai, and Chennai, along with three Cyclonic Warning Centers (CWCs) situated in Visakhapatnam, Ahmedabad, and Pune. The Meteorological Centre is based in Hyderabad.
• The cyclone warning system is organized in a three-tier structure, wherein the ACWCs and CWCs play a crucial role in issuing bulletins and warnings.
• Within this structure, specific warnings are issued by the ACWCs and CWCs for various purposes and target groups, such as fishermen, ships, the Navy, the press, All India Radio, the aviation sector, registered users, and others.

List of Cyclone Nivar Affected Areas in India

About Tropical Cyclones

As per the Indian Meteorological Department (IMD), a tropical cyclone is a dangerous weather event causing heavy rainfall, strong winds (known as gale winds), and storm surges when it reaches land. Tropical cyclones are powerful low-pressure systems with extremely forceful winds.

• A tropical cyclone is characterized by a steep pressure gradient, evident in closely spaced isobars.
• At the center of the cyclonic depression is a low-pressure region known as the eye of the cyclone.
• Cyclones exhibit an anticlockwise circulation in the Northern Hemisphere and a clockwise circulation in the Southern Hemisphere.
• The impact of cyclones includes substantial rainfall in the affected and surrounding areas.
• A cyclonic approach is marked by a rapid decline in the barometric reading, overcast skies, robust winds, and an oppressive climate.

Favorable conditions for the formation of a Tropical Cyclone

• Expansive sea surface coverage.
• Sea surface temperature surpasses 27 degrees.
• Presence of the Coriolis force.
• Minimal fluctuations in vertical wind speed.
• Elevated humidity levels.

Facts about Cyclone Nivar for UPSC

Check the Facts about Cyclone Nivar for UPSC provided below in the table:

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