Cyclonic winds - class-VIII

Cyclone Vardah was a severe cyclonic storm that struck the east coast of India in December 2016, making it one of the most intense storms of that year in the North Indian Ocean.

Satellite imagery allows meteorologists to monitor the cloud patterns, such as the spiral bands and the eye of the cyclone, to estimate the track and intensity of the storm.

The name 'Vardah' was suggested by Pakistan. The naming of cyclones in the North Indian Ocean is done by a panel of member countries, including Pakistan.

The panel on Tropical Cyclones for the North Indian Ocean consists of eight countries: Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, and Thailand. Japan is not part of this regional panel.

Hurricanes are tropical cyclones that form over the North Atlantic Ocean and the Northeast Pacific Ocean. Those in the Northwest Pacific are called Typhoons, and those in the Indian Ocean are simply called Cyclones.

The name 'Vardah' was suggested by Pakistan and it means 'red rose' in Arabic/Urdu/Persian context.

The naming of cyclones in the North Indian Ocean is a collaborative effort by the member countries of the WMO/ESCAP Panel on Tropical Cyclones, which includes India, Sri Lanka, Bangladesh, and others.

Water Spout is a phenomenon that results in the formation of vertical water funnel at sea. A rotating column of water and spray formed by a whirlwind occurring over the sea or other body of water.

Since sea surface temperatures and humidity both directly correlate with chances of cyclone formation, the Bay of Bengal is a more likely target because it gets higher rainfall, and because the sluggish winds around it keep temperatures relatively high: about 28 degrees around the year. Warm air currents enhance this surface temperature and aid the formation of cyclones.

In addition, the Bay receives higher rainfall and constant inflow of freshwater from the Ganga and Brahmaputra rivers. This means that the Bay’s surface water keeps getting refreshed, making it impossible for the warm water to mix with the cooler water below, making it ideal for depression. 

Western disturbances are extratropical storms originating in the Mediterranean region that bring winter rainfall to the northwestern parts of India, particularly Punjab, Haryana, and Rajasthan.

Cyclone and anticyclone are two important types of cyclonic activity. The atmospheric disturbance which involves a closed circulation about a low-pressure center, anticlockwise in the northern hemisphere and clockwise in the southern hemisphere, are called cyclones. On the other hand, anticyclone plays a much less important role in the weather-drama at the surface of the earth in comparison with the cyclone. It denotes on atmospheric system that is just opposite of the cyclonic system.

When the wind is spirally moving in towards a low-pressure center then it is called a cyclone. A cyclone has a low pressure at its center and high pressure on the surrounding sides. The wind movement is anti-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

When the wind blows from the high-pressure center towards the low-pressure center this atmospheric disturbance is known as a cyclone. Cyclone blows anticlockwise in the southern hemisphere. It blows anticlockwise because of the Coriolis force produced by the rotation of the earth.

An
area of closed, circular fluid motion rotating in the same direction as the
Earth is known as a cyclone. It has a lower pressure inside and higher pressure
outside. The center of the cyclone is known as the eye. It has a diameter of 20-50 km. It
is the point about which the rest of the storm rotates. It has the lowest
atmospheric pressure.

When high speed wind blows from high pressure towards the low pressure centre is known as cyclone. Their frequency, direction and intensity varies from place to place. In terms of direction it blows clock wise in southern hemisphere and anti-cyclone wise in  northern hemisphere. The frequncy and intensity also varies with its location and depending on that cyclones are known in different names in different places.

An anti-cyclone originates when a mass of air with high pressure is encircled by that with low pressure. When such condition occurred the relatively cool and dry wind from high pressure blows out to the surrounding low pressure.  While blows out, the wind turns round and round. In anti-cyclone  there exits high pressure at the center, it is called the center or eye of anti-cyclone.

In the absence of rotation, the wind tends to blow from areas of high pressure to areas of low pressure. The stronger the pressure differences between a high-pressure system and a low-pressure system, the stronger the wind. The coriolis force caused by Earth's rotation gives winds within high-pressure systems their clockwise circulation in the northern hemisphere as the wind moves outward and is deflected right from the center of high pressure and anticlockwise circulation in the southern hemisphere as the wind moves outward and is deflected left from the center of high pressure. Friction with land slows down the wind flowing out of high-pressure systems and causes wind to flow more outward from the center.

Western disturbances, specifically the ones in winter, bring moderate to heavy rain in low-lying areas and heavy snow to mountainous areas of the Indian Subcontinent. They are the cause of most winter and pre-monsoon season rainfall across northwest India.

Natural disasters like cyclones often show early meteorological symptoms or signs, allowing authorities and the public time to make necessary preparations to mitigate damage.

The eye is a region of mostly calm weather at the center of strong tropical cyclones. The eye of a storm is a roughly circular area, typically 30–65 km (20–40 miles) in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather occurs.

In the American continents, particularly the Atlantic and Northeast Pacific regions, tropical cyclones are referred to as hurricanes.

Tropical cyclones require warm ocean waters, high humidity, and atmospheric instability. A peninsular land mass is not a requirement; in fact, land masses often weaken cyclones by cutting off the moisture supply.

The eye of a cyclone is the central region of the storm, characterized by low pressure, light winds, and clear or calm skies, surrounded by the eyewall where the most intense weather occurs.

Effective disaster management for cyclones involves a multi-faceted approach, including strict coastal regulations, robust communication systems, and safe infrastructure construction, all of which are essential.

The International Strategy for Disaster Reduction (ISDR) is a global framework established within the United Nations for the promotion of action to reduce social vulnerability and risks of natural hazards and related technological and environmental disasters.

Its main purpose is to facilitate, in an inter-agency effort Governments and communities in disaster-prone areas in integrating the management of risk into their development policies, programs and projects. 

When a tropical cyclone forms in the western Pacific between 180 degrees and 100 degrees East longitude, it's called a typhoon. So, Japan, China, the Philippines, etc., get typhoons.

An anemometer is commonly used to measure wind speed. Wind speed, or wind flow velocity, is a fundamental atmospheric quantity. Wind speed is caused by air moving from high pressure to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer but can also be classified using the older Beaufort scale which is based on people's observation of specifically defined wind effects.

Cyclone Nilofar was a very severe cyclonic storm that formed in the Arabian Sea in late October 2014.

The National Institute of Disaster Management (NIDM) is a premier national organization working for human resource development at national and regional level in the area of disaster mitigation and management. The NIDM came into existence since October 16, 2003 by a Government of India order upgrading the National Centre for Disaster Management (NCDM), which was located at Indian Institute of Public Administration, New Delhi.

Tornado is a dark funnel shaped cloud that reaches from the sky to the ground. Most of the tornadoes are weak. A violent tornado can travel at speeds of about 300 km/h. Tornadoes may form within cyclones. In our country they are not very frequent. 

Both Agromet advisory services and Potential fishing zone advisory services provide critical information that helps in disaster preparedness and mitigation for coastal communities during cyclones. These systems allow for timely warnings and protective measures.

Tropical cyclones in the North Indian Ocean, including the Bay of Bengal, are most frequent during the post-monsoon season, specifically in October and November.

Tropical cyclones in the Bay of Bengal are technically classified as cyclonic storms. They are not called typhoons (Pacific) or hurricanes (Atlantic/Eastern Pacific).