2011 North Indian Ocean cyclone season

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
2011 North Indian Ocean cyclone season
First system formed February 2, 2011
Last system dissipated December 31, 2011
Strongest storm1 Thane – 969 hPa (mbar), 140 km/h (85 mph) (3-minute sustained)
Depressions 10
Deep depressions 6
Cyclonic storms 2
Very severe cyclonic storms 1
Super cyclonic storms 0
Total fatalities 360 total
Total damage At least $277 million (2011 USD)
1Strongest storm is determined by lowest pressure
North Indian Ocean tropical cyclone seasons
2009, 2010, 2011, 2012, 2013

The 2011 North Indian Ocean cyclone season was the least active tropical cyclone season in the North Indian Ocean since 1993.[1] Only two cyclone storms have formed throughout the year, far below the average of 4-6. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. The scope of this article is limited to the Indian Ocean in the Northern Hemisphere, east of the Horn of Africa and west of the Malay Peninsula. There are two main seas in the North Indian Ocean — the Arabian Sea to the west of the Indian subcontinent, abbreviated ARB by the India Meteorological Department (IMD); and the Bay of Bengal to the east, abbreviated BOB by the IMD.

This is the first season to have only two named storms since the 1993 North Indian Ocean cyclone season. However, multiple Depressions along with Cyclonic Storm Keila and Very Severe Cyclonic Storm Thane wreaked damage worth at least US$1.64 million and killing some 360 people overall. It is believed that El Niño, a quasiperiodic climate pattern that causes a rise in surface pressure over the Indian Ocean and makes the region drier is the main cause behind the below normal activity in the basin.[2]

Season summary

This season, 9 depressions developed out of low pressure areas, with six intensifying further into deep depressions, two deep depressions have developed into cyclonic storms, and one cyclonic storm intensified into a severe cyclonic storm. The first depression of the season developed on February 2 about 300 km (190 mi) to the east of Colombo, Sri Lanka. The depression brought isolated rainfall to parts of Sri Lanka, while remaining near stationary before weakening into an area of low pressure early the next day.

Depression ARB 01 formed in early June near India, before Deep Depression BOB 02 formed a few days later. Land Depression 01 formed on July 22, and dissipated a day later. Depression BOB 03 formed on September 22, and soon made landfall on India. Depression BOB 03 dissipated the next day, on September 23. October was a much more active month, as Deep Depression BOB 04 and Deep Depression ARB 02 both formed, during this period of time. Then Cyclonic Storm Keila formed in November and came ashore in Oman, before Depression ARB03 formed and dissipated near the Oman coast.

Storms

Depression BOB 01

Depression (IMD)
150px 150px
Duration February 2 – February 3
Peak intensity 45 km/h (30 mph) (3-min)  1002 hPa (mbar)

On February 2, the IMD upgraded an area of low pressure, located approximately 100 km southeast of Pottuvil, Sri Lanka, to a depression, giving it the designation "BOB 01."[3] The convection in the system gradually increased and the system drifted towards land.[4] Early on the next day, the IMD downgraded the system into a remnant low because of its proximity to land and weakened.[5]

Following catastrophic floods in December 2010 and January 2011, the depression brought additional rainfall to Sri Lanka.[6] The subsequent floods and mudslides killed 18 people and affected nearly 1.2 million. Numerous roads were washed away as reservoirs across the island overflowed their banks and inundated surrounding communities. In the wake of the floods, the Government of Sri Lanka allocated 33 billion Sri Lankan rupee ($287 million US$) for rehabilitation.[7]

Depression ARB 01

Depression (IMD)
Tropical storm (SSHWS)
150px 150px
Duration June 11 – June 12
Peak intensity 45 km/h (30 mph) (3-min)  996 hPa (mbar)

In early June, a low pressure area formed over the Arabian Sea. The low pressure area remained stationary and became more well marked. On June 11, the IMD upgraded the area of low pressure to a depression giving it the designation "ARB 01".[8] The same day, the JTWC designated the system as Tropical Cyclone 01A.[9] At that time it was located approximately 180 kilometres (110 mi) northwest of Mumbai, India and 150 kilometres (93 mi) southeast of Veraval, Gujarat. Later, on June 12, IMD reported that the depression had crossed the Saurashtra coast of India about 25 km east of Diu.[10] Later on the same day, the IMD reported that the depression had weakened into a well-marked low pressure area in their last bulletin for the system.[11]

Deep Depression BOB 02

Deep Depression (IMD)
150px 150px
Duration June 16 – June 23
Peak intensity 65 km/h (40 mph) (3-min)  978 hPa (mbar)

On June 16, the IMD upgraded an area of well marked low pressure (WML), located about 100 km east-southeast of Sagar Island, 150 km southeast of Kolkata and 150 km west-southwest of Khepupara (Bangladesh), to a depression, giving it the designation "BOB 02".[12] On June 16, the depression intensified into a deep depression and crossed the West Bengal coast about 100 km east of Sagar Island.[13] On the same day, at 1900 hrs UTC, the JTWC issued a Tropical Cyclone Formation Alert (TCFA).[14] The system drifted further inland and the JTWC cancelled their TCFA the next day.[15] The system weakened into a depression by June 18 and laid centered over Jharkhand.[16] The depression gradually drifted westwards and moved onto northern Madhya Pradesh by June 21.[17] and slowly dissipated into a well marked low pressure area on June 23.[18]

Heavy rains across West Bengal triggered widespread flooding and landslides that killed at least six people.[19]

Land Depression 01

Depression (IMD)
150px 150px
Duration July 22 – July 23
Peak intensity 35 km/h (25 mph) (3-min)  990 hPa (mbar)

On July 21 as the Madden–Julian oscillation entered its fifth phase, the Bay of Bengal became favourable for tropical cyclogenesis.[20] As a result of this and an Upper tropospheric cyclonic vortex, an area of low pressure developed on July 21, over the Gangetic West Bengal about 50 km (30 mi) to the southeast of Daltonganj.[20] During the next day the IMD reported that the low pressure area had intensified into a land depression, with peak 3-minute sustained windspeeds of 35 km/h (25 mph).[20] During that day, the depression moved towards the northwest under the influence of a monsoon trough before it weakened into a low pressure area during July 23.[21] Under the influence of the system, the Indian states of Madhya Pradesh, Rajasthan, Gujarat, Chhattisgarh and Vidarbha saw widespread heavy rainfall, however, no economic damage was reported.[20]

Depression BOB 03

Depression (IMD)
150px 150px
Duration September 22 – September 23
Peak intensity 45 km/h (30 mph) (3-min)  995 hPa (mbar)

Late on September 20, an area of low pressure developed approximately 200 nautical miles (370 km; 230 mi) south of Chittagong, Bangladesh.[22] Under the influence of strong vertical wind shear and monsoonal activity in the Bay of Bengal, the system couldn't strengthen and the JTWC later reported that the system dissipated.[23] However, on September 22, the IMD started monitoring the system as a Depression and initiated bulletins on the system, designating it with BOB 03.[24] Late on that day, BOB 03 drifted northwest and made landfall over north Orissa close to Balasore.[25] After moving further northwestwards, the depression remained practically stationary over Jharkhand. By the evening of September 23, IMD reported that the depression had weakened into a well-marked low pressure area in their final bulletin for the system, as the storm dissipated to a remnant low.[26]

As the depression made landfall, heavy rains threatened flood for the second time within two weeks in the Bramhani and Baitarani rivers. By the evening of September 22, 90 villages in Jajpur were displaced to the sudden spontaneous swelling of the river Baitarani.[27] At least 38 people were killed in flood-related incidents across Orissa. The worst flooding took place in the Jajpur and Bhadrak districts where at least 18 people perished.[28]

Deep Depression BOB 04

Deep depression (IMD)
Tropical storm (SSHWS)
150px 150px
Duration October 19 – October 20
Peak intensity 55 km/h (35 mph) (3-min)  1000 hPa (mbar)

A low pressure area over the Bay of Bengal intensified, and was upgraded to Depression BOB 04 on October 19, 2011.[29] The depression intensified slightly and the IMD upgraded the storm into a Deep Depression the same day.[30] Later on the same day, the JTWC upgraded the system into a Tropical Storm. The system moved inland and weakened into a depression. The weakening process took place gradually as the storm moved more inland and dissipated into a remnant low.[31]

Along the border between Myanmar and Bangladesh, torrential rains produced devastating flash floods. In the Magway region, roughly 2,000 homes were washed away by a "mass of water" and more than 6,000 remained flooded for days. Initial estimates placed damage from the storm at $1.64 million.[32] At least 215 people were confirmed to have been killed with many more missing. Officials in the hard-hit town of Pakokku believed that the death toll would exceed 300 as residents searched for missing relatives days after the floods.[33] Similar to what took place in the wake of Cyclone Nargis in 2008, journalists were warned by the Government not to take pictures of the disaster. Overall, it is the deadliest tropical cyclone in the North Indian Ocean since Cyclone Aila in 2009.[34]

Cyclonic Storm Keila

<templatestyles src="Module:Hatnote/styles.css"></templatestyles>

Main article: Cyclone Keila
Cyclonic storm (IMD)
Tropical storm (SSHWS)
150px 150px
Duration October 29 – November 4
Peak intensity 65 km/h (40 mph) (3-min)  996 hPa (mbar)

Under the influence of a low-level trough, a low-pressure area formed over the Arabian Sea in late October. The system organized and the IMD designated the system Depression "ARB 02".[35] The depression moved toward the Middle East during the next few days and intensified into a Deep Depression on November 1.[36] In the morning of November 2, IMD upgraded the deep depression into a cyclonic storm and was named Keila.

Heavy rains from the storm in Oman are blamed on at least 14 deaths and 200 people are injured. High flood waters prompted the evacuation of hospitals in the capital city of Muscat.[37] On November 3, JTWC downgraded the storm into a tropical depression. On the same day, JTWC issue their final advisories on this system. In evening, IMD downgraded the storm into a deep depression. On November 4, IMD downgraded the depression into an area of low pressure issuing its final advisory on the system.[38]

Deep Depression ARB 03

Deep depression (IMD)
Tropical storm (SSHWS)
150px 150px
Duration November 6 – November 10
Peak intensity 55 km/h (35 mph) (3-min)  1000 hPa (mbar)

On November 6, the IMD upgraded an area of low pressure area into a Depression, designating it ARB 03. The system was forecasted to intensify into a deep depression and move towards the Gulf of Aden in the next 72 hours.[39] On the same day a TCFA was issued by the JTWC.[40] The IMD upgraded the storm into a deep depression on November 8, and forecasted that it would intensify into a cyclonic storm within the next 24 hours[41] which was followed by an upgrade to a tropical storm by JTWC.[42] After an influence of unfavorable conditions and landmass, the system weakened and JTWC issued its final warning.[43] Soon the IMD downgraded the storm into a depression.[44] On November 10, the storm dissipated into a low pressure area.[45]

Deep Depression ARB 04

Deep depression (IMD)
Tropical storm (SSHWS)
150px 150px
Duration November 26 – December 1
Peak intensity 55 km/h (35 mph) (3-min)  998 hPa (mbar)

On November 26, at 11:30 am IST, the IMD upgraded a low pressure south of India near Cape Comorin into a depression, designating the name ARB 04.[46] The same day, the JTWC upgraded the storm from a tropical depression to a Tropical Storm and named it 05A.[47] Extensive damage and loss of life has been reported in Sri Lanka, where the storm is linked with heavy rains which have caused 19 deaths and damage to 5,700 homes.[48] The IMD upgraded the storm to a Deep Depression on November 28.[49] Later on November 29 the IMD downgraded the storm into a depression.[50] Following the downgrading of the storm by IMD, the JTWC on November 30 issued their final warning on 05A. The IMD, on December 1, reported that the storm had weakened into a well-marked low pressure area, and issued the final bulletin for the system.[51]

Very Severe Cyclonic Storm Thane

<templatestyles src="Module:Hatnote/styles.css"></templatestyles>

Main article: Cyclone Thane
Very severe cyclonic storm (IMD)
Category 2 tropical cyclone (SSHWS)
150px 150px
Duration December 25 – December 31
Peak intensity 140 km/h (85 mph) (3-min)  969 hPa (mbar)

On December 23, the JTWC reported that a tropical disturbance had developed within the monsoon trough about 1,545 km (960 mi) to the east of Medan in Indonesia.[52][53] Convection surrounding the system had started to consolidate over a weak low level circulation centre, that was being fed by an enhanced westerly flow associated with the precursor system to Tropical Cyclone Benilde.[52][53] Over the next couple of days the disturbance gradually developed further while moving towards the northwest, before the JTWC issued a TCFA on the system during December 25 before designating as Tropical Cyclone 06B later that day.[53][54][55] The IMD also reported during December 25, that the disturbance had organised sufficiently to be declared Depression BOB 05, while it was located about 1,000 km (620 mi) to the southeast of Chennai, India.[56] During the next day, the IMD reported that the depression had intensified into a Deep Depression, before later that day reporting that it had intensified into Cyclonic Storm Thane.[57][58] As it was named, Thane started to turn towards the west under the influence of a subtropical ridge of high pressure before its development slowed as strong outflow and marginally favourable sea surface temperatures fought with persistent easterly vertical wind shear.[59][60]

Early on December 28, the JTWC reported that Thane had become equivalent to a category one hurricane on the SSHS before later that day the IMD reported that Thane had become the first Very Severe Cyclonic Storm of the season.[61][62] During December 28, Thane continued to intensify, and developed a small pinhole eye, before the JTWC reported that Thane had peaked early on December 29 with 1-minute sustained wind speeds of 165 km/h (105 mph).[63][64] The IMD then followed suit and reported that the system had peaked as a Very Severe Cyclonic Storm with 3-minute sustained windspeeds of 140 km/h (85 mph).[65] During the rest of that day, the system continued to move westwards and weakened slightly as it started to interact with land. Thane then made landfall as a very severe cyclonic storm early on December 30 on the north Tamil Nadu coast between Cuddalore and Pondicherry.[66] After making landfall, Thane rapidly weaken into a depression before the JTWC issued their final advisory during December 30, while the IMD continued to monitor the remnants of Thane until the depression weakened into a well marked low-pressure area on December 31.[66]

Overall, Thane was responsible for the deaths of 46 people with total damage to India, estimated at between 13 – 15 billion rupees (235 – 275 million USD).[nb 1][68]

Season effects

Name Dates active Peak classification Sustained
wind speeds		 Pressure Land areas affected Damage
(USD)		 Deaths Refs
BOB 01 February 2 – 3 Depression 45 km/h (30 mph) 1000 Sri Lanka 18
ARB 01 June 11 – 12 Depression 45 km/h (30 mph) 996 India None
BOB 02 June 16 – 23 Deep Depression 65 km/h (40 mph) 978 India 6
LAND 01 July 22 – 23 Depression 40 km/h (25 mph) 990 India 0
BOB 03 September 22 – 23 Depression 45 km/h (30 mph) 995 India 42
BOB 04 October 19 – 20 Deep Depression 55 km/h (35 mph) 1000 Bangladesh, Myanmar 1.64 million 215
Keila October 29 – November 4 Cyclonic Storm 65 km/h (40 mph) 996 Oman, Yemen 14
ARB 03 November 6 – November 10 Deep Depression 55 km/h (35 mph) 1000
No land areas affected.
ARB 04 November 26 – December 1 Deep Depression 55 km/h (35 mph) 998 Lakshadweep, India, Sri Lanka None 19
Thane December 25 – December 31 Very Severe Cyclonic Storm 140 km/h (85 mph) 969 India 235 – 275 million 46 [68]
Season Aggregates
10 systems February 2 – December 30 140 km/h (85 mph) 969 hPa (28.62 inHg) >$277 million >360


See also

Notes

  1. ↑ The damage total was originally reported in crore of rupees and was converted via the Oanda Corporation website using the rates for January 1, 2012.[67]

References

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.(Note: Creation of an account in the website is required in order to access data.)
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  19. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  20. ↑ 20.0 20.1 20.2 20.3 Lua error in package.lua at line 80: module 'strict' not found.
  21. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  24. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  25. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  26. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  27. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  28. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  29. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  30. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  31. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  32. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  33. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  34. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  35. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  36. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  37. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  38. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  39. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  40. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  41. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  42. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  43. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  44. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  45. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  46. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  47. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  48. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  49. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  50. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  51. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  52. ↑ 52.0 52.1 Lua error in package.lua at line 80: module 'strict' not found.
  53. ↑ 53.0 53.1 53.2 Lua error in package.lua at line 80: module 'strict' not found.
  54. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  55. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  56. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  57. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  58. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  59. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  60. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  61. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  62. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  63. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  64. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  65. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  66. ↑ 66.0 66.1 Lua error in package.lua at line 80: module 'strict' not found.
  67. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  68. ↑ 68.0 68.1 Lua error in package.lua at line 80: module 'strict' not found.

External links

Retrieved from "https://infogalactic.com/w/index.php?title=2011_North_Indian_Ocean_cyclone_season&oldid=2789365"