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Cumulative track map of all North Indian Ocean cyclones from 1970 to 2005
Cumulative track map of all North Indian Ocean cyclones from 1970 to 2005

In the Indian Ocean north of the equator, tropical cyclones can form throughout the year on either side of India, although most frequently between April and June, and between October and December.

Sub-basins

Very severe cyclonic storms (Luban and Titli) over the Arabian Sea and the Bay of Bengal in October 2018
Very severe cyclonic storms (Luban and Titli) over the Arabian Sea and the Bay of Bengal in October 2018

The North Indian Ocean is the least active basin, contributing only seven percent of the world's tropical cyclones. However the basin has produced some of the deadliest cyclones in the world, since they strike over very densely populated areas.[1] The Regional Specialized Meteorological Centre (RSMC) is the India Meteorological Department (IMD) and it is responsible to monitor the basin, issues warning and name the storms.[2]

The basin is divided into two sub-basins  – the Bay of Bengal and the Arabian Sea.[3]

The Bay of Bengal, located in the northeast of the Indian Ocean. The basin is abbreviated BOB by the India Meteorological Department (IMD).[4] The United States's Joint Typhoon Warning Center unofficially designates as B to classify storms formed in the Bay of Bengal.[5] The Bay of Bengal's coast is shared among India, Bangladesh, Myanmar, Sri Lanka and western part of Thailand.[6] This sub-basin is the most active and produced one of the deadliest cyclones of all time.[7] The most intense cyclone in the bay was the 1999 Odisha cyclone.[8]

The Arabian Sea is a sea located in the northwest of the Indian Ocean. Tropical cyclones in the basin are abbreviated ARB by the India Meteorological Department (IMD).[4] The United States's Joint Typhoon Warning Center unofficially designates as A to classify storms formed in the Arabian Sea.[9] The Arabian Sea's coast is shared among India, Yemen, Oman, UAE, Iran, Pakistan, Sri Lanka, Maldives and Somalia.[10] Monsoons are characteristic of the Arabian Sea and responsible for the yearly cycling of its waters. In summer, strong winds blow from the southwest to the northeast, bringing rain to the Indian subcontinent. Cyclones are rare in the Arabian Sea, but the basin can produce strong tropical cyclones.[10] Cyclone Gonu was the strongest and the costliest recorded tropical cyclone in the basin.[11]

History of the basin

The systematic scientific studies of tropical systems in the Bay of Bengal and Arabian Sea was started during the 19th century by Henry Piddington.[12] Piddington utilised meteorological logs of vessels that navigated the seas and published a series of memoirs, in the Journal of the Asiatic Society of Bengal between 1839 and 1858.[12] These memoirs gave accounts and tracks of individual storms in the Bay of Bengal and the Arabian Sea.[12]

During the 2004 post monsoon season the IMD started to name tropical cyclones within the basin, with the first one named Cyclone Onil during September 2004.[13] During 2015 a modification to the intensity scale took place, with the IMD and WMO calling a system with 3-minute maximum sustained wind speeds between 90 knots (165 km/h; 105 mph) and 120 knots (220 km/h; 140 mph) an extremely severe cyclonic storm.[14]

A study analysing the spring season of tropical cyclones in the Bay of Bengal found increases in both pre-monsoon precipitation and tropical cyclone intensity as a result of enhanced large-scale monsoon circulation after 1979. The deepened monsoon trough in the Bay of Bengal not only affects cyclone frequency and timing, but also acts to direct more cyclones towards Myanmar. Increased anthropogenic aerosols likely contributed to such a regional climate change.[15]

Climatology

Formation and frequency

On average only five to six tropical cyclones form in the basin each year. Tropical cyclones form in the months of March to June and October to December, with peaks at May and November. Most of these storms form in the Bay of Bengal: either in the southeastern Bay of Bengal, or in the Andaman Sea, or as a remnant of a typhoon from the South China Sea.[8] High sea surface temperatures and humidity makes the bay more favourable to tropical cyclone development.[16] There are many tropical cyclones in the West Pacific; this may be another reason for increased[clarification needed] tropical cyclogenesis in the Bay, as it shares a fair portion of the increased quota of ACE. Meanwhile, the storms in the Arabian Sea mostly form over south-eastern part of the Arabian Sea or a remnant of a tropical cyclone from the Bay of Bengal, however the frequency of cyclogenesis in the Arabian Sea is generally less, due to cooler sea surface temperature and high wind shear.[8] However a strong positive Indian Ocean Dipole may cause an increase of tropical cyclogenesis than usual[clarification needed] which was seen the 2019 season.[17] Very few tropical cyclones develop in the months of June to September (Monsoon months) because of high vertical wind shear. These storms form and peak as depressions or deep depressions before making landfall in Odisha or West Bengal. Another reason is the low life span in the sea[clarification needed] which also avoids the intensification of these low-pressure systems.[8]

Movement

Most of the storms move in a north-westerly direction and starts curving either towards southwest or northeast. There's a higher frequency of recurving towards northeast rather going southwest. In the Arabian Sea these storms mostly move in north-westerly direction targeting the Arabian Peninsula, however in some case these storm moves north-eastwards after crossing the 15°N latitude and strikes the Gujarati coast. In the Bay of Bengal, storms generally moves north-westwards until reaching the east coast and then moves north eastwards.[18]

Intensification

Intensification probability is maximum in the month of April, May and November in case of a depression becoming a cyclonic storm and severe cyclonic storm. More than half of the depressions intensify into a storm and a quarter intensify into a cyclone in these months.[19]

Landfall

In the Arabian Sea, most storms dissipate offshore without making landfall, but a significant number of tropical cyclones also impact the west coast, particularly the states of Gujarat and Maharashtra. The remaining 11 percent makes landfall in either the Arabian Peninsula, Horn of Africa or Pakistan.[20] In rare cases, some storms makes landfall in the Iran like Cyclone Gonu did back in 2007.[21] Other than Gonu, two storms like Cyclone Yemyin and Kyarr made some or major impact in Iran.[22][23]

In the Bay of Bengal, most of the storms strikes either the Indian state of Odisha or West Bengal and a significant number of storms hit the states of Andhra Pradesh and Tamil Nadu. 30 percent of the cyclones strike the countries of Bangladesh, Sri Lanka and Myanmar while the remaining 13 percent just dissipates off shore without making landfall.[20]

Climate change

See also: Climate change

After a series of devastating cyclones in 2018, rising number of cyclones in the Arabian Sea in 2019 and rising trend of rapid intensification in 2020 and 2021, many climatologist agrees that climate change have caused these activities. On average five cyclonic storm occurs every year the Arabian Sea, however in 2019 eight cyclonic storms formed becoming the highest tropical cyclones formation in the sub-basin, which was tied with the 1902 season.[24][25] Research found that in recent decades the sea surface temperatures has risen up by 1.2–1.4 °C (34.2–34.5 °F) in the Arabian Sea.[25] During Cyclone Amphan underwent a rapid intensification, sea surface temperatures were as high as 33 °C (91 °F) in the Bay of Bengal and the Arabian Sea recorded 32 °C (90 °F) sea surface temperature, before the formation of Cyclone Nisarga.[26] According to the Union Ministry of Earth and Science, the frequency of very severe cyclonic storm has risen up by one per decade in last two decades, despite the decrease of overall frequency of the basin in the last two decades.[25] Higher temperatures caused the cyclones to become more powerful and lead to tropical cyclone formation faster. Rising sea level also caused higher storm surge.[26] Researchers also predict that cyclones will be deadlier and stronger as the trend of warming sea surface temperatures continues. Rising sea levels also may cause severe flooding, strong storm surges and will inundate coastal towns.[26]

Seasons

Historical storm formation by month between 1990 and 2020
10
20
30
40
50
60
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
  •   Super Cyclone
  •   Extremely Severe
  •   Very Severe
  •   Severe
  •   Cyclonic Storm
  •   Deep Depression
  •   Depression

Before 1890

Main article: Pre-1890 North Indian Ocean cyclone seasons

1890s

Main article: 1890s North Indian Ocean cyclone seasons

Year D CS SCS Notes
1890 10 4 1
1891 13 4 3 Total includes 1 Land Severe Cyclonic Storm
1892 12 7 2
1893 12 10 4
1894 12 6 0
1895 11 5 4
1896 10 8 3
1897 12 6 8
1898 13 7 3
1899 7 3 0
References[27]

1900s

Main article: 1900s North Indian Ocean cyclone seasons

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1900 10 3 1
1901 6 3 2
1902 13 7 5
1903 14 8 2
1904 9 4 0
1905 10 6 0
1906 11 7 1
1907 15 8 4
1908 9 6 1
1909 8 8 4
References[27]

1910s

Main article: 1910s North Indian Ocean cyclone seasons

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1910 6 5 2
1911 7 5 4
1912 9 6 2
1913 10 6 2
1914 8 4 2
1915 9 6 0
1916 14 8 5
1917 10 3 1
1918 11 5 0
1919 11 6 3
References[27]

1920s

Main article: 1920s North Indian Ocean cyclone seasons

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1920 9 5 0
1921 10 4 1
1922 13 6 6
1923 16 4 3
1924 13 6 0
1925 20 7 3
1926 13 10 3
1927 18 7 2
1928 13 7 0
1929 15 6 0
References[27]

1930s

Main article: 1930s North Indian Ocean cyclone seasons

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1930 14 10 1
1931 11 5 1
1932 14 6 2
1933 16 8 3
1934 16 5 0
1935 15 6 2
1936 17 6 3
1937 19 6 2
1938 10 4 4
1939 19 7 3
References[27]

1940s

Main article: 1940s North Indian Ocean cyclone seasons

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1940 16 8 5
1941 19 8 4
1942 14 5 2
1943 14 7 1
1944 19 8 2
1945 15 3 2
1946 17 5 1
1947 18 4 2
1948 18 6 3
1949 12 1 1
References[27]

1950s

Main article: 1950s North Indian Ocean cyclone seasons

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1950 16 4 0  SCS  Sixteen Unknown Unknown
1951 15 4 2  SCS  Fifteen Unknown Unknown
1952 17 4 2
1953 10 1 1
1954 14 1 0
1955 13 6 2
1956 14 4 2
1957 7 4 2
1958 12 5 2
1959 16 6 3
References[27]

1960s

This ESSA 3 satellite image was taken on November 3, 1966, at 0819 UTC of a tropical cyclone striking Madras, India
This ESSA 3 satellite image was taken on November 3, 1966, at 0819 UTC of a tropical cyclone striking Madras, India
Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1960 15 5 3  VSCS  Ten 20,299 >$9.4 million Vast majority of the fatalities resulted from two cyclones striking East Pakistan three weeks apart
1961 18 5 4  SCS  Winnie 11,525 Unknown Three land depressions developed this season
1962 13 5 3  VSCS  Twelve 769 $34.5 million Deadliest storm, Harriet, crossed over from the Western Pacific
1963 17 6 4  SuCS  Three 11,735 Unknown
1964 16 7 5  SuCS  "Rameswaram" >1,827 >$150 million
1965 14 6 4
1966 18 8 6
1967 15 6 4
1968 13 7 4  SuCS  "Burma"
1969 14 6 1  ESCS  Twelve
References[27]

1970s

Year D CS SCS Strongest
storm
Deaths Damage
(USD)
Notes
1970 15 7 3  ESCS  "Bhola" 300,000-500,000 86.4 million The Bhola cyclone is the deadliest tropical cyclone recorded worldwide
1971 15 7 6  ESCS  "Odisha"
1972 18 7 6  ESCS  09B
1973 16 6 3  SCS  14B
1974 12 7 3  VSCS  06B
1975 20 7 4  ESCS  02A
1976 14 10 7  ESCS  02A
1977 18 5 5  SuCS  "Andhra Pradesh" up to 50,000 $192 million Devastated Krishna Delta area in Andhra Pradesh
1978 14 5 3  SuCS  "Sri Lanka" 1,000+
1979 11 5 4  ESCS  01B
References[27]

1980s

Year D DD CS SCS VSCS ESCS SuCS Strongest
storm
Deaths Damages
(USD)
Notes
1980 14 14 5 0 0 0 0  CS  BOB 02
1981 12 12 5 3 3 0 0  VSCS  BOB 03
1982 19 11 8 5 3 3 0  ESCS  BOB 01
1983 7 4 2 1 1 1 0  ESCS  03B
1984 7 7 4 3 3 2 0  ESCS  03B 430
1985 15 15 6 1 1 0 0  VSCS  01B 11,107
1986 8 3 1 0 0 0 0  CS  02B 11
1987 9 8 5 3 1 0 0  VSCS  01B
1988 9 5 5 3 2 2 0  ESCS  "Bangladesh" 6,740 $13 million
1989 10 5 3 2 1 1 1  SuCS  "Kavali" 1,785 $25.27 million Typhoon Gay crossed over from the West Pacific Basin
References[27]

1990s

Year D DD CS SCS VSCS ESCS SuCS Strongest
storm
Deaths Damage
(USD)
Notes and References
1990 11 6 2 2 1 1 1  SuCS  BOB 01 967 $600 million [28][29]
1991 9 4 3 1 1 1 1  SuCS  "Bangladesh" >138,000 $1.5 billion [29]
1992 13 11 7 2 1 1 0  ESCS  Forrest 189 $69 million Forrest crossed over from the West Pacific Basin
1993 5 4 2 2 2 0 0  ESCS  BOB 02 714 $216 million
1994 5 5 4 2 2 1 0  ESCS  "Bangladesh" 315 $12.5 million
1995 8 6 3 2 2 1 0  ESCS  BOB 07 554 $46.3 million
1996 10 8 6 4 2 0 0  VSCS  "Andhra Pradesh" 2,075 $1.9 billion
1997 9 7 3 2 1 1 0  ESCS  "Bangladesh" 117 Unknown
1998 13 10 6 5 3 1 0  ESCS  "Gujarat" >10,212 $3 billion
1999 10 8 5 3 3 2 1  SuCS  "Odisha" 15,780 $5 billion The Odisha cyclone is the strongest cyclone recorded in the Northern Indian Ocean.
References[27]

2000s

Year D DD CS SCS VSCS ESCS SuCS Strongest
storm
Deaths Damage
(USD)
Notes
2000 7 6 5 2 2 2 0  ESCS  "South India" 238 $185 million
2001 6 5 4 1 1 1 0  ESCS  "Gujarat" 108 $104 million
2002 7 7 4 1 0 0 0  SCS  "West Bengal" 182 $25 million
2003 7 5 3 3 1 0 0  VSCS  "Sri Lanka" 358 $163 million
2004 10 7 4 4 1 1 0  ESCS  "Myanmar" 587 $130 million
2005 12 7 3 0 0 0 0  CS  Pyarr 273 $21.4 million
2006 12 6 3 2 1 1 0  ESCS  Mala 623 $6.7 million
2007 11 8 4 2 2 2 1  SuCS  Gonu 16,248 $6.4 billion
2008 10 7 4 1 1 1 0  ESCS  Nargis >138,927 $15.4 billion The deadliest cyclone season since 1970
Second-costliest cyclone season on record
2009 8 6 4 1 0 0 0  SCS  Aila 421 $618 million
References[27]

2010s

Year D DD CS SCS VSCS ESCS SuCS Strongest
storm
Deaths Damages
(USD)
Notes
2010 8 6 5 4 2 1 0  ESCS  Giri 402 $2.99 billion The most active season since 1998
2011 10 6 2 1 1 0 0  VSCS  Thane 360 $277 million
2012 5 5 2 0 0 0 0  CS  Nilam 128 $56.7 million The first depression of the year did not develop until October 10
2013 10 6 5 4 3 1 0  ESCS  Phailin 323 $1.5 billion Featured Phailin, the first Category 5-equivalent cyclone since Sidr in 2007
2014 8 5 3 2 2 2 0  ESCS  Nilofar 183 $3.4 billion
2015 12 9 4 2 2 2 0  ESCS  Chapala 363 $358 million
2016 10 5 4 1 1 0 0  VSCS  Vardah 401 $5.4 billion
2017 10 6 3 2 1 0 0  VSCS  Ockhi 834 $3.65 billion
2018 14 9 7 5 3 1 0  ESCS  Mekunu 343 $4.33 billion The most active season since 1992
2019 12 11 8 6 6 3 1  SuCS  Kyarr 173 $11.5 billion Earliest cyclonic storm in the basin
First Super Cyclonic Storm since 2007
99 68 43 27 21 10 1 Kyarr 3510 $33.5 billion
References[27]

2020s

Year D DD CS SCS VSCS ESCS SuCS Strongest
storm
Deaths Damages
(USD)
Notes
2020 9 6 5 4 3 1 1  SuCS  Amphan 269 $15.8 billion First super cyclonic storm in the Bay of Bengal since 1999
Featured the costliest cyclone ever recorded in the basin, Amphan
Costliest North Indian cyclone season on record
2021 7 5 4 3 2 1 0  ESCS  Tauktae 230 $5.31 billion
2022 10 4 1 1 0 0 0  SCS  Asani 35 None
Total 26 15 10 8 5 2 1 Amphan 534 $21.11 billion

Records

See also

Notes

References

  1. ^ "Cyclone Tauktae Strikes India". earthobservatory.nasa.gov. May 17, 2021. Retrieved June 5, 2021.
  2. ^ "Activities of RSMC, New Delhi". www.rsmcnewdelhi.imd.gov.in. Retrieved June 5, 2021.
  3. ^ "2021 North Indian Ocean Cyclone Season". disasterphilanthropy.org. Retrieved June 5, 2021.((cite web)): CS1 maint: url-status (link)
  4. ^ a b "Acronyms". www.rsmcnewdelhi.imd.gov.in. Retrieved June 5, 2021.
  5. ^ "TROPICAL CYCLONE 02B (TWO) WARNING NR 001". www.metoc.navy.mil. Pearl Harbour, Hawaii: Joint Typhoon Warning Center. May 24, 2021. Archived from the original on May 24, 2021. Retrieved May 24, 2021.
  6. ^ "Bay of Bengal | bay, Indian Ocean". Encyclopædia Britannica. Retrieved June 3, 2021.
  7. ^ "Why Bay of Bengal is hotbed of worst tropical cyclones? As Yaas hits Odisha, here's all you need to know". The Financial Express. May 26, 2021. Retrieved June 5, 2021.
  8. ^ a b c d e "Frequently Asked Questions on Tropical Cyclones" (PDF). IMD. Retrieved May 31, 2021.((cite web)): CS1 maint: url-status (link)
  9. ^ "TROPICAL CYCLONE 01A (ONE) WARNING NR 001". www.metoc.navy.mil. Pearl Harbour, Hawaii: Joint Typhoon Warning Center. May 14, 2021. Archived from the original on May 14, 2021. Retrieved May 14, 2021.
  10. ^ a b "History of cyclones in the Arabian sea". Pakistan Weather Portal (PWP). April 10, 2011. Retrieved May 30, 2021.
  11. ^ "Tropical Cyclone Gonu". earthobservatory.nasa.gov. June 7, 2007. Retrieved May 30, 2021.
  12. ^ a b c Best track data of tropical cyclonic disturbances over the north Indian Ocean (PDF) (Report). India Meteorological Department. July 14, 2009. Retrieved October 31, 2015.
  13. ^ RSMC — Tropical Cyclones New Delhi (January 2005). Report on Cyclonic Disturbances over North Indian Ocean during 2014 (PDF) (Report). p. 2. Archived (PDF) from the original on April 2, 2015.
  14. ^ Third Joint Session of Panel on Tropical Cyclones & Typhoon Committee February 9–13, 2015 (PDF). Bangkok, Thailand: World Meteorological Organization. p. 10. Archived (PDF) from the original on April 19, 2016.
  15. ^ Wang, Shih-Yu; Buckley, Brendan M.; Yoon, Jin-Ho; Fosu, Boniface (2013). "Intensification of premonsoon tropical cyclones in the Bay of Bengal and its impacts on Myanmar". Journal of Geophysical Research: Atmospheres. 118 (10): 4373–4384. doi:10.1002/jgrd.50396. ISSN 2169-8996.
  16. ^ "Why Bay of Bengal is hotbed of world's worst tropical cyclones?". Get Bengal. Retrieved June 2, 2021.
  17. ^ "What is the Indian Ocean Dipole? Explain its connection with the Indian monsoons – Civilsdaily". Retrieved June 2, 2021.
  18. ^ "Movement". www.rsmcnewdelhi.imd.gov.in. Retrieved May 30, 2021.
  19. ^ "Intensification". www.rsmcnewdelhi.imd.gov.in. Retrieved May 30, 2021.
  20. ^ a b "Landfall". www.rsmcnewdelhi.imd.gov.in. Retrieved May 30, 2021.
  21. ^ "WHO EMRO | Experience of cyclone Gonu in the Islamic Republic of Iran: lessons learned | Volume 16, issue 12 | EMHJ volume 16, 2010". www.emro.who.int. Retrieved June 7, 2021.
  22. ^ "MODIS Web". modis.gsfc.nasa.gov. Retrieved June 7, 2021.
  23. ^ "NASA - Hurricane Season 2007: Tropical Cyclone 3B". www.nasa.gov. Retrieved June 7, 2021.
  24. ^ "Statement on Climate of India during 2019" (PDF). IMD. January 6, 2020. Retrieved June 5, 2021.((cite web)): CS1 maint: url-status (link)
  25. ^ a b c "Cyclone Tauktae shows why north Indian Ocean is now whacky". www.downtoearth.org.in. Retrieved June 5, 2021.
  26. ^ a b c Sarkar, Soumya (June 5, 2020). "Cyclones rise as climate change heats up Indian Ocean". India Climate Dialogue. Retrieved June 5, 2021.
  27. ^ a b c d e f g h i j k l m Unattributed (August 31, 2010). "Annual frequency of cyclonic disturbances (Maximum sustained windspeeds of 17 knots or more), Cyclones (34 knots or more) and Severe Cyclones (48 knots or more) over the Bay of Bengal (BOB), Arabian Sea (AS) and land surface of India" (PDF). India Meteorological Department. Archived from the original (PDF) on August 5, 2011. Retrieved August 20, 2011.
  28. ^ Regional Specialised Meteorological Centre (RSMC) – Tropical Cyclones, New Delhi (January 1992). Report on Cyclonic Disturbances (Depressions and Tropical Cyclones) over North Indian Ocean in 1990 (PDF) (Report). India Meteorological Department. Archived (PDF) from the original on January 15, 2015. Retrieved February 22, 2015.
  29. ^ a b Unattributed (June 26, 2008). "Historical records of Severe Cyclones which formed in the Bay of Bengal and made landfall at the eastern coast of India during the period from 1970-1999". India Meteorological Department. Archived from the original on September 25, 2014. Retrieved August 20, 2011.
  30. ^ "Cyclone Fani: How 2019 was different from 1999 super cyclone". The Indian Express. May 12, 2019. Retrieved June 3, 2021.
  31. ^ "Cyclone Nargis cost Burma $4bn, says UN report". the Guardian. July 21, 2008. Retrieved June 3, 2021.
  32. ^ "Fifty Years of the Cyclone That Triggered a Civil War and Created Bangladesh". The Wire. Retrieved June 3, 2021.
  33. ^ "Hurricanes: Science and Society: 1970- The Great Bhola Cyclone". www.hurricanescience.org. Retrieved June 3, 2021.
  34. ^ "REPORT ON CYCLONIC DISTURBANCES OVER NORTH INDIAN OCEAN DURING 2006" (PDF). IMD. January 2007. Archived (PDF) from the original on April 12, 2013. Retrieved June 4, 2021.
  35. ^ "Anemometer Failed to Read Wind Speed of 1999 Cyclone". www.outlookindia.com/. Retrieved June 4, 2021.
  36. ^ "Alarming Rise in the Number and Intensity of Extreme Point Rainfall Events over the Indian Region under Climate Change Scenario" (PDF). Indian Institute of Tropical Meteorology: 19. August 2009.