Cyclones_ Factfile

Cyclones - Factfile

                

What is a Cyclone?
The word cyclone has been derived from Greek word ‘cyclos’ which means ‘coiling of a snake’. The word cyclone was coined by Heary Piddington who worked as a Rapporteur in Kolkata during British rule. The terms “hurricane” and “typhoon” are region specific names for a strong “tropical cyclone”. Tropical cyclones are called “Hurricanes” over the Atlantic Ocean and “Typhoons” over the Pacific Ocean. 

A tropical cyclone 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.

Cyclone Prone Areas in India
India has a coastline of about 7,516 km of which 5,400 km is along the mainland. The entire coast is affected by cyclones with varying frequency and intensity. Although the North Indian Ocean (the Bay of Bengal and Arabian Sea) generates only about 7% of the world's cyclones (5 to 6 Tropical Cyclones per year) their impact is comparatively high and devastating, especially when they strike the coasts bordering the North Bay of Bengal.

Thirteen coastal states and Union Territories (UTs) in the country are affected by tropical cyclones. Four states (Tamil Nadu, Andhra Pradesh, Orissa and West Bengal) and one UT (Puducherry) on the east coast and one state (Gujarat) on the west coast are more vulnerable to cyclone hazards.

The India Meteorological Department (IMD) is the nodal government agency that provides weather services related to cyclones in India.

Classification of Cyclones in India: 
The criteria followed by Meteorological Department of India (IMD) to classify the low pressure systems in the Bay of Bengal and in the Arabian Sea as adopted by World Meteorological Organisation (WMO) are as under: 

Type of Disturbances

Associated Wind Speed in the Circulation

Low pressure Area

Less than17 knots (<31 kmph)

Depression

17 to 27 knots (31 to 49 kmph)

Deep Depression

28 to 33 knots (50 to 61 kmph)

Cyclonic Storm

34 to 47 knots (62 to 88 kmph)

Severe Cyclonic Storm

48 to 63 knots (89 to 118 kmph)

Very Severe Cyclonic Storm

64 to 119 knots (119 to 221 kmph)

Super Cyclonic Storm

120 knots and above (222 kmph and above)

Recent Cyclones of Andhra Pradesh

Name of the Cyclone

Year of Occurrence

Hudhud

12 October 2014

Lehar

25 November 2013

Helen

21 November 2013

Nilam

October 2012

Laila

May 2010

Khai-Muk

November 2008

Yemyin

June 2007

The recent deadly cyclones that hit Indian coast
Cyclone Phailin (2013) – The Cyclone Phailin is a category 5 storm that struck the Odisha and Andhra coast on 11 October 2013 causing massive destruction in the region- affecting 12 million people. Phailin is a Thai word which means Sapphire. This cyclone prompted India's biggest evacuation in 23 years with more than 5,50,000 people being moved from the coastline in Odisha and Andhra Pradesh to safer shelters. Phailin brought very heavy rain of over 600 mm at many stations of Odisha. It also damaged crops worth Rs 2,400 crore and claimed over 40 lives. Loses due to Cyclone Phailin were estimated to be around rupees 420 crore.

Cyclone Nilam (2012) - Cyclonic Storm Nilam was the deadliest tropical cyclone to directly affect south India that made landfall near Mahabalipuram on October 31 as a strong cyclonic storm with peak winds of 85 kmph. Nilam caused economic losses of around Rs 100 crore because of torrential rain. 

Cyclone Thane (2011) - Thane was the strongest tropical cyclone of 2011 that became a very severe cyclonic storm on December 28, as it approached the Indian states of Tamil Nadu and Andhra Pradesh and made landfall at north Tamil Nadu coast between Cuddalore and Puducherry on December 30. Thane left at least 46 people dead in Tamil Nadu and Puducherry. Cuddalore and Puducherry were the worst affected areas. 

Cyclone Laila (2010) - Severe cyclonic storm Laila made a landfall in Andhra Pradesh on the 20 May 2010 and caused major flooding and damage along its path. Ongole in Andhra Pradesh recorded heavy rainfall of about 460 mm in just two days. Another town Addanki received the highest rainfall of 522 mm. The state government faced a loss of over Rs 500 crore due to Cyclone Laila.

Cyclone Jal (2010) - Cyclone Jal killed at least 54 people in India alone. About 300 thousand hectares of cropland was devastated by the cyclone. The remnants of Jal continued to move northwest, brought light to moderate spells of rain in India's warmest state of Rajasthan and also in Gujarat.

Cyclone Phyan (2009) - Cyclonic Storm Phyan developed as a tropical disturbance in the Arabian Sea to the southwest of Colombo in Sri Lanka on November 4, 2009 and made landfall in south India on November 7. Massive damage to property was reported in coastal districts of Maharashtra, such as Ratnagiri, Raigad, Sindhudurg, Thane and Palghar.

Cyclone Nisha (2008) - Over 180 people were killed in Tamil Nadu alone due to heavy rain and floods caused by the cyclone. Orathanadu, in Thanjavur District in Tamil Nadu received over 990 mm of rain within 24 hours. The total amount of rainfall received from Nisha was about 1280 mm. The damage caused by the cyclone was estimated to be about 3789 crores.

The 30 Deadliest Tropical Cyclones in World History

Rank

Name / Areas of Largest Loss

Year

Ocean Area

Deaths

1.

Great Bhola Cyclone, Bangladesh

1970

Bay of Bengal

500,000

2.

Hooghly River Cyclone, India and Bangladesh

1737

Bay of Bengal

300,000

3.

Haiphong Typhoon, Vietnam

1881

West Pacific

300,000

3.

Coringa, India

1839

Bay of Bengal

300,000

5.

Backerganj Cyclone, Bangladesh

1584

Bay of Bengal

200,000

6.

Great Backerganj Cyclone, Bangladesh

1876

Bay of Bengal

200,000

7.

Chittagong, Bangladesh

1897

Bay of Bengal

175,000

8.

Super Typhoon Nina, China

1975

West Pacific

171,000

9.

Cyclone 02B, Bangladesh

1991

Bay of Bengal

140,000

9.

Cyclone Nargis, Myanmar

2008

Bay of Bengal

140,000

11.

Great Bombay Cyclone, India

1882

Arabian Sea

100,000

12.

Hakata Bay Typhoon, Japan

1281

West Pacific

65,000

13.

Calcutta, India

1864

Bay of Bengal

60,000

14.

Swatlow, China

1922

West Pacific

60,000

15.

Barisal, Bangladesh

1822

Bay of Bengal

50,000

15.

Sunderbans coast, Bangladesh

1699

Bay of Bengal

50,000

15.

India

1833

Bay of Bengal

50,000

15.

India

1854

Bay of Bengal

50,000

19.

Bengal Cyclone, Calcutta, India

1942

Bay of Bengal

40,000

19.

Bangladesh

1912

Bay of Bengal

40,000

19.

Bangladesh

1919

Bay of Bengal

40,000

22.

Canton, China

1862

West Pacific

37,000

23.

Backerganj (Barisal), Bangladesh

1767

Bay of Bengal

30,000

24.

Barisal, Bangladesh

1831

Bay of Bengal

22,000

25.

Great Hurricane, Lesser Antilles Islands

1780

Atlantic

22,000

26.

Devi Taluk, SE India

1977

Bay of Bengal

20,000

26.

Great Coringa Cyclone, India

1789

Bay of Bengal

20,000

28.

Bangladesh

1965 (11 May)

Bay of Bengal

19,279

29.

Nagasaki Typhoon, Japan

1828

Western Pacific

15,000

30.

Bangladesh

1965 (31 May)

Bay of Bengal

12,000