Disclaimer: Copyright infringement not intended.

Context:

Cyclone Fengal made landfall over Puducherry.  As a precaution, the Tamil Nadu government moved around 471 people to six relief centres in Tiruvallur and Nagapattinam districts.

About Cyclone Fengal:

The name "Fengal," proposed by Saudi Arabia, reflects the Arabic linguistic and cultural identity of the region.

Cyclones in the North Indian Ocean are named by a panel comprising 13 member countries of the World Meteorological Organization (WMO) and the United Nations Economic and Social Commission for Asia and the Pacific (UNESCAP), including nations like Bangladesh, India, Iran, Maldives, and Pakistan.

Each member submits a list of names used sequentially for cyclones, and names are not reused. Following Fengal, the next names in line are Shakhti, contributed by Sri Lanka, and Montha, contributed by Thailand.

What is a Cyclone?

A is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an anticyclone).

Cyclones are characterized by inward-spiraling winds rotating about a low-pressure zone.

The largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale (the synoptic scale). Warm-core cyclones such as tropical cyclones and subtropical cyclones also lie within the synoptic scale

Conditions of cyclone formation:

• High sea temperatures of at least 27°C.
• Converging winds near the ocean surface forcing air to rise and form storm clouds.
• Winds that do not vary greatly with height - known as low wind shear. This allows the storm clouds to rise vertically to high levels;
• Sufficient distance from the equator for a spin such as the Coriolis force to take effect.

What is the ‘landfall’ of a cyclone?

Landfall is the event of a tropical cyclone coming onto land after being over water.

As per the India Meteorological Department (IMD), a tropical cyclone causes landfall when the center of the storm – or its eye – moves over the coast.

A landfall should not be confused with a ‘direct hit’, which refers to a situation where the core of high winds (or eyewall) comes ashore but the center of the storm may remain offshore.

As per the US National Oceanic and Atmospheric Administration (NOAA), because the strongest winds in a tropical cyclone are not located precisely at the center, a cyclone’s strongest winds can be experienced over land even if landfall does not occur.

What is the damage caused by a cyclone’s landfall?

The damage caused by the landfall will depend on the severity of the cyclone – marked by the speed of its winds.

If the cyclonic storm is “very severe”, the impact may include extensive damage to kutcha houses, partial disruption of power and communication lines, minor disruption of rail and road traffic, potential threat from flying debris and flooding of escape routes.

How long does a landfall last?

Landfalls can last for a few hours, with their exact duration depending on the speed of the winds and the size of the storm system.

Cyclones lose their intensity once they move over land because of a sharp reduction of moisture supply and an increase in surface friction.

This means that while landfalls are often the most devastating moments of cyclones, they also mark the beginning of its end.

Source:

INDIAN EXPRESS