Biparjoy: Unraveling the Power and Impact of Tropical Cyclones

Tropical Cyclone Biparjoy

India is a South Asian country bounded by the Arabian Sea, the Indian Ocean, and the Bay of Bengal. India lies in the north of the Indian Ocean which is most vulnerable to being affected by tropical cyclones in the basin from the east or west.

An average of about 2 to 4 tropical cyclones affect India every year, while most of these tropical cyclones affect the east coast of the Indian states of West Bengal, Odisha, Andhra Pradesh, and Tamil Nadu. One in these 2 to 4 cyclones hit the west coast, most of them hitting the states of Gujarat, Maharashtra, Goa, Karnataka, and Kerala.

Cyclone Biparjoy was one such powerful tropical cyclone, classified as ‘Extremely Severe’. It formed over the east-central Arabian Sea and made landfall near the India-Pakistan border.

Biparjoy was the third depression and second cyclonic storm of the 2023 North Indian Ocean cyclone season. It originated from a depression that was recorded by the India Meteorological Department (IMD) on 6^th June before intensifying into a cyclonic storm. It accelerated northeastward and strengthened into a Category 3-equivalent tropical cyclone and extremely severe cyclonic storm. The cyclone made landfall in Naliya, India on June 16^th.

Meteorological Formation and Landform

• On 1^st June, the India Meteorological Department (IMD) began monitoring the possibility of a cyclonic circulation in the Arabian Sea.
• A cyclonic circulation formed in the Arabian Sea on 5^th On the same day, a cyclonic circulation resulted in the formation of a low-pressure area.
• The next day, it significantly intensified into a depression. The Joint Typhoon Warning Center (JTWC) issued a tropical cyclone warning over the system. The IMD upgraded the depression to a deep depression and subsequently to a cyclonic storm.
• On 7^th June, the IMD upgraded the system to a severe cyclonic storm with winds of 100 km/h. Biparjoy upgraded to a severe cyclonic storm within the next few hours and became a Category- 2 equivalent tropical cyclone.
• Biparjoy unexpectedly intensified rapidly and became a Category 3-equivalent cyclone on 11^th It reached its peak intensity as an extremely intense cyclonic storm, with maximum 3-minute sustained winds of 165 km/h.
• The Cyclone gradually weakened with convective banding over the Northern Hemisphere. The structure of the cyclone deteriorated rapidly as the convection became asymmetric.
• Biparjoy reduced its windspeed to 95 km/h and made landfall near Nalia, India on June 16^th. Shortly after landing, the JTWC terminated the system warning. The cyclone was now finally weakened into a depression.
• The depression was later designated as a low-pressure area by the IMD on June 19, prompting the withdrawal of the advisory on the system.

Preparation and Impact in India

• The Indian Meteorological Department issued a warning to local authorities in Gujarat on June 12^th, urging them to prepare for evacuation. Residents in coastal areas have been advised to stay indoors as the storm approaches land.
• The national and state disaster response teams were deployed to the vulnerable areas by the Gujarat government. Army, Navy, and state and national relief forces supported the evacuation efforts.
• Besides Gujarat, the IMD predicted heavy downpours due to the cyclone in several states of India’s western and southern coasts, in certain regions of Maharashtra, Karnataka, and Goa.
• As per the reports, an estimated 94,000 individuals were safely evacuated from the coastal regions. Flood and blackout warnings were issued.
• Train services were suspended and operations at the major ports of Kandla and Mundra were halted. The Indian Coast Guard evacuated 50 workers from an oil rig off the coast of Gujarat.
• During the cyclone, 1,206 pregnant women were safely transferred from the affected area to various hospitals and health and wellness centers, of which 707 women gave birth.
• Heavy rains and strong winds lashed the coastal areas of Gujarat, killing three people in Kutch and Rajkot districts. Trees were destroyed and walls collapsed due to severe weather conditions.
• Strong waves swept away tents situated on Mandvi Beach in the Kutch area. Dwarka experienced high tide. The neighboring state of Maharashtra also witnessed heavy rains and high tidal waves.
• A total of 23 people were injured and 4,600 villages were left without electricity. 5 people lost their lives in Rajasthan.

What is a Tropical Cyclone?

A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, closed lower-level atmospheric circulation, strong winds, and thunderstorms that produce heavy rainfall and thunderstorms. Depending on its location and strength, tropical cyclones are known by various names such as hurricanes, typhoons, tropical storms, cyclonic storms, tropical depressions, or cyclones.

A ‘hurricane’ is a severe tropical cyclone that occurs in the Atlantic Ocean or the northeast Pacific Ocean, and a ‘typhoon’ occurs in the northwest Pacific Ocean. Comparable storms in the Indian Ocean, South Pacific, or (rarely) South Atlantic are called “tropical cyclones”, and such storms in the Indian Ocean are also called “severe cyclones”.

‘Tropical’ refers to the geographical origin of this system, forming only over tropical seas. ‘Cyclone’ refers to winds that rotate outside the central open eye and cause surface winds to blow counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

A tropical cyclone is a general term for non-frontal synoptic-scale low-pressure systems that are warm in color over tropical or subtropical waters around the world.

The opposite direction of rotation is caused by the Coriolis effect. Tropical cyclones are usually formed in large bodies of warm water. They get their energy from the evaporation of water in the ocean, which turns into clouds and rain when moist air rises and cools when saturated. The strong rotating winds of tropical cyclones are the result of the conservation of angular momentum imparted by the Earth’s rotation as it flows inland toward the axis of rotation. Consequently, it rarely forms at 5° of the equator.

The main source of energy for these storms is warm ocean water. Therefore, these storms are usually strongest over or near water and weaken very quickly over land. This makes coastal areas more vulnerable to tropical cyclones compared to inland areas.

Records of Tropical Cyclones in India

Historically, tropical cyclones have occurred around the world for thousands of years, and one of the earliest tropical cyclones is estimated to have occurred in Western Australia around 4000 AD.

• The strongest tropical cyclone to produce an earthquake was the 1999 Odisha Cyclone in Odisha. The minimum pressure is 912 mbar (26.93 inHg), and the maximum wind speed is 260 km/h.
• The deadliest tropical cyclone was Cyclone Amphan in 2020, which hit Odisha and West Bengal. The cost of the damage was $ 13 billion US dollars, beating the record for Cyclone Nargis.
• The deadliest was the Indian cyclone of 1839, which hit present-day Andhra Pradesh. It caused more than 300,000 deaths and the destruction of 20,000 ships.
• The wettest tropical cyclone was the 1968 Super Cyclone which hit West Bengal with 2,300 mm of rainfall.

The Coriolis Effect and its Impact on Weather

The Coriolis effect describes the escape of objects that are not firmly attached to the Earth as they travel long distances around the Earth. The Coriolis effect is responsible for many weather conditions.

In particular, the Earth rotates faster at the Equator than at the poles. The Earth is wider at the Equator, so the equatorial region travels about 1,600 kilometers per hour to rotate in 24 hours. Near the poles, the Earth rotates up to 0.00008 kilometers per hour. This causes an apparent deflection known as the Coriolis Effect.

Fluids that flow over large areas, such as air currents, seem to be inclined to the right in the Northern Hemisphere. The Coriolis effect is reversed in the Southern Hemisphere, where currents are seen to roll to the left. The effect of the Coriolis effect depends on the speed of the Earth and the speed of the body or fluid affected by the Coriolis effect. The effect of the Coriolis effect is more significant at high speeds or long distances.

The development of weather patterns such as cyclones and trade winds are examples of the Coriolis effect.

A cyclone is a low-pressure system that draws air into a center or “eye”. In the Northern Hemisphere, fluid from a high-pressure system moves to the right of a low-pressure system. As the air masses are drawn into the cyclone from all directions, they escape and the storm system – the storm – seems to rotate counterclockwise. In the Southern Hemisphere the current turns to the left. As a result, the storm system appears to rotate clockwise.

The influence of the Coriolis effect outside the solar system helps determine consistent wind patterns on Earth.

For example, when warm air rises near the equator, it flows toward the poles. In the Northern Hemisphere, this warm air current cools to the right (east) as it moves north. The current descends on land at about 30°N latitude. As the current subsides, it gradually flows from northeast to southwest toward the Equator. This regular circulation pattern of air masses is known as trade winds.

How are Tropical Cyclones named?

The practice of naming tropical cyclones began several years ago to help quickly identify storms in warning messages, as names are believed to be easier to remember than numbers and technical terms. There is a strict procedure for creating a list of names of tropical cyclones in an ocean basin by the regional tropical cyclone organization responsible for that basin at annual/biannual meetings. Cyclones in each ocean basin worldwide are designated by the Regional Special Meteorological Center (RSMC) and the Tropical Cyclone Warning Center (TCWC). There are six RSMCs in the world as well as five TCWCs under the India Meteorological Department (IMD).

For Asia and the Pacific region, a group of nations called WMO/ ESCAP, abbreviated for World Meteorological Organization/ United Nations Economic and Social Commission is responsible for naming the Tropical cyclones.

The nations that are involved are Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, Thailand, Iran, Qatar, Saudi Arabia, United Arab Emirates, and Yemen.

The Tropical Cyclones in the Indian Ocean and South Pacific receive their names in alphabetical order, and women’s and men’s names are alternated annually.

Who Named Biparjoy and what does it mean?

Cyclone Biparjoy was coined by Bangladesh and the word means “disaster” or “calamity” in Bengali.

Disclaimer: The above-mentioned information has been sourced from: Wikipedia, Websites of National Geography (education), and the World Meteorological Organization.