UPSC CSE Mains Syllabus: GS-1- Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.,

In news:


Nisarga was a name given by Bangladesh in a list, which has been formulated by a group of countries. The word ‘Nisarga’ means nature. 

 “If you take the Arabian Sea, the ocean is generally cooler than the Bay of Bengal and also has opposing winds in the atmosphere, especially during early monsoon or during monsoon. At the lower level of atmosphere, the winds may be blowing in one direction and on the upper level, it may be blowing in the opposite direction.  This prevents the cyclone from developing vertically upwards.”

This is the key reason for states like Maharashtra and Gujarat to have been relatively unscathed by cyclones in the past. But that is changing now.

Is Climate Change Causing Cyclone Nisarga?

Increasing frequency of cyclones:

Last year, however, was slightly unusual as the Arabian Sea saw the most frequent and intense cyclonic activity in more than 100 years, according to India Meteorological Department. Five cyclones originated in the area in 2019 — Vayu, Hikka, Kyarr, Maha and Pavan – when normally only one or two are formed.

How Will Nisarga Impact Mumbai?

But waterlogging is a very strong possibility. The impact of the waterlogging that is likely to ensue could have only been countered had the State implemented the recommendations of the Madhav Chitale Committee after studying the 2005 Mumbai floods that claimed thousands of lives.

The committee came up with four key observations and recommendations.

  1. The drainage linesin Mumbai were inadequate.
  2. Whatever available drainage line was there, a lot of them have been blocked or closed up by the societies or slum.
  3. Aside from encroachment, Mumbai has also lost a large chunk of its mangrovesover the last few decades.
  4. These mangroves are usually the first line of defencewhen battling natural disasters like cyclones and flooding.
Tropical cyclone:· A tropical cyclone (TC) is a rotational low-pressure system in tropics when the central pressure falls by 5 to 6 hPa from the surrounding and maximum sustained wind speed reaches 34 knots (about 62 kmph).· It is a vast violent whirl of 150 to 800 km, spiraling around a centre and progressing along the surface of the sea at a rate of 300 to 500 km a day.  Landfall:· A Landfall is the intersection of the center of a tropical cyclone with a coastline, according to the US National Hurricane Center.· Typically, in strong tropical cyclones, a landfall occurs when the eye of the cyclone moves over land. 

 Cyclones are classified on the basis of the wind speed.

What are the Precautions Taken by the State?

Source:” Indian Express“.

Possible UPSC CSE Mains Question:

What is the reason behind the increasing trend of cyclonic activity in the Arabian sea in recent times?