Current Affairs

Jigyasa

  1. Home
  2. Current Affairs

ARTICLE OF THE DAY - TROPICAL CYCLONE - CYCLONE OKCHI

Sat, 02 December 2017 | DISASTER MANAGEMENT

Syllabus- General Studies III - Disaster Management

Cyclone Ockhi
Background

             Cyclone Ockhi has claimed at least 12 lives so far even as it intensified into a ‘severe’ cyclone on Friday, causing heavy rains in the coastal areas of Kerala and south Tamil Nadu.

What is a tropical cyclone
  • Tropical Cyclones Tropical cyclones are violent storms that originate over oceans in tropical areas and move over to the coastal areas bringing about large scale destruction caused by violent winds, very heavy rainfall and storm surges.
  • The strong rotating winds of a tropical cyclone are a result of the conservation of angular momentum imparted by the Earth's rotation as air flows inwards toward the axis of rotation. As a result, they rarely form within 5° of the equator
  • While six factors appear to be generally necessary, tropical cyclones may occasionally form without meeting all of the following conditions.
Cyclones In India

India's long coastline of nearly 7,500 km consists of 5,400 km along the mainland, 132 km in Lakshadweep and 1,900 km in the Andaman and Nicobar Islands. About 10 per cent of the World's tropical cyclones affect the Indian coast. Of these, the majority have their initial genesis over the Bay of Bengal and strike the east coast of India. On an average, five to six tropical cyclones form every year, of which two or three could be severe. Cyclones occur frequently on both the west coast in the Arabian Sea and the east coast in the Bay of Bengal.More cyclones occur in the Bay of Bengal than in the Arabian Sea and the ratio is approximately 4:1.

How cyclone ‘Ockhi’ got its name
  • The name Ockhi was given by Bangladesh which in Bengali means ‘eye’.
  • The World Meteorological Organisation (WMO) and the United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) started the tropical cyclone naming system in 2000.
  • Tropical cyclones are named to provide ease of communication between forecasters and the general public regarding forecasts, watches, and warnings.
  • Eight north Indian Ocean countries — Bangladesh
  • India, the Maldives, Myanmar, Oman, Pakistan, Sri Lanka and Thailand, gave eight names each which was combined into a list of 64 names. One name from each country is picked in an order to name the cyclones.
Facts for prelims

Disasters and nodal ministries according to National Disaster management Plan (NDMP)

(Irrelevant information..too factual and unimportant to remember)

A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; and Willy-willies in the Western Australia, while in the south Pacific or Indian Ocean, comparable storms are referred to simply as “tropical cyclones” or “severe cyclonic storms”.

Factors that contribute to formation of cyclones
  • Water temperatures of at least 26.5 °C
  • Rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone
  • High humidity is needed
  • More than 555 km (345 mi) or five degrees of latitude away from the equator, ( To provide minimum required coriolis force )
Why is Bay of Bengal more prone to cyclones?
1. Sea Surface Temperatures(SST’s)

The ideal temperature is around 25–27 degrees Celsius. This temperature helps to sustain the moisture and provide enough

National Disaster Management Authority (NDMA) The Government of India established the NDMA in 2005, headed by the Prime Minister. Under the DM Act 2005, the NDMA, as the apex body for disaster management, shall have the responsibility for laying down the policies, plans, and guidelines for disaster management for ensuring timely and effective response to disaster.

force(provided all the other conditions like remnants of the typhoon would pass on to wind-direction, land-terrain are met) to the cyclone. Bay of Bengal is relatively warmer compared to Arabian Sea and the average SST is higher.

2. Additional influx of moisture from South China Sea

Whenever Bay of Bengal experiences a cyclone or a depression, we can also see that South China Sea would be experiencing a typhoon. The leftover moisture and the Bay of Bengal.

3. Terrain of the Coromandel Coast

The East Coast does not have any strong mountain range to block (or at least reduce the ferocity) of the winds. The West Coast has the Western Ghats close by.

  • The previous storm Mora that caused severe flooding across Northeast India in May was named by Thailand. Mora is the name of one of the healing stones and also means star of the sea. The next cyclone will be named Sagar — a name given by India.
How cyclone are classified in India

(No need to remember the speeds. Just undersatnd the concept of classification based on speed and why different storms have different divastating effects…...ofcourse because of different speed.)

Cyclone mitigation according to National disaster plan