Very Severe Cyclonic Storm Hamoon[a] (/hɑːˈmun/) was a moderately strong tropical cyclone that affected Bangladesh, India, and Myammar during October 2023. The fourth named storm of the 2023 North Indian Ocean cyclone season, Hamoon formed from a low-pressure area over the west-central Bay of Bengal on 21 October. Initially slowly developing, after it entered an area favorable for development, it rapidly intensified, peaking as a very severe cyclonic storm on 24 October. However, soon after, Hamoon weakened due to wind shear, later making landfall in Bangladesh as a severe cyclonic storm. Once inland, Hamoon degenerated into a low-pressure area, last being noted on 26 October.

Very Severe Cyclonic Storm Hamoon
Hamoon near peak intensity while approaching Bangladesh on 24 October
Meteorological history
Formed21 October 2023
Dissipated25 October 2023
Very severe cyclonic storm
3-minute sustained (IMD)
Highest winds120 km/h (75 mph)
Lowest pressure984 hPa (mbar); 29.06 inHg
Category 2-equivalent tropical cyclone
1-minute sustained (SSHWS/JTWC)
Highest winds155 km/h (100 mph)
Lowest pressure978 hPa (mbar); 28.88 inHg
Overall effects
Fatalities5
Injuries63
Damage$250 million (2023 USD)
Areas affectedBangladesh, Myanmar, Northeast India
[1]

Part of the 2023 North Indian Ocean cyclone season

Prior to Hamoon's landfall, officials in Bangladesh ordered the evacuation of over 1.5 million people as it was expected to have a severe impact on the nation. As Hamoon made its devastating landfall in Bangladesh on 26 October, five people died from Hamoon's winds. Additionally, 63 others sustained injuries. Over 6 million lost power, primarily in the port of Cox's Bazar, where several days after Hamoon made landfall, over 5 million were still without power. Elsewhere, a weakening Hamoon mainly brought light rainfall to India and Myanmar. In total, according to Aon, the cyclone caused around $250 million in damage.

Meteorological history

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Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
  Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

On 12 October, in their extended range outlook, the India Meteorological Department (IMD) noted that in a few days, tropical cyclonegenesis was likely to occur in the Bay of Bengal.[3] Several days later, on 17 October, they began monitoring a cyclonic circulation over the southeastern Bay of Bengal.[4] Developing, on 20 October, a low-pressure area formed from this circulation over the southcentral Bay of Bengal.[5] A few hours later, the Joint Typhoon Warning Center (JTWC) began tracking the system, noting that the low-level circulation was in an favorable environment for development, with low 5–10 mph (10–20 km/h) vertical wind shear and warm sea surface temperatures (SSTs) of 29–30 °C (84–86 °F), only offset by the disturbance's poor outflow.[6] As a result, early the next day, the disturbance developed into a well-marked low-pressure area.[7] Consolidating as it generated good outflow aloft,[8] by the night of 21 October, the disturbance had became a depression.[9]

 
Infrared imagery of Hamoon rapidly intensifying off the coast of Bangladesh late on 23 October.

Initially tracking north-northwestward, after it recurved northwestward the next day, the depression developed further, becoming a deep depression at 12:00 UTC that day.[3] Around six hours later, the JTWC issued a TCFA on the deep depression, noting that it had developed convective banding across all quadrants and good poleward outflow.[10] As a result, the JTWC recognized the system as Tropical Cyclone 06B around that time,[11] prior to it intensifying into a cyclonic storm and being named Hamoon by the IMD.[12] Early the next day, the depression would encounter an environment with high SSTS of 29–30 °C (84–86 °F), low to moderate vertical wind shear, strong low-level vorticity, and convergence in the vicinity of the cyclone alongside strong upper-level divergence above the system, causing the system to undergo rapid intensification.[3]

Intensifying into a severe cyclonic storm early on 24 October,[13] Hamoon soon further developed, becoming a very severe cyclonic storm just a few hours later,[14] peaking with 3-minute sustained winds of 75 mph (120 km/h) around that time.[3] A few hours later, Hamoon would peak with 1-minute sustained winds of 100 mph (155 km/h), making it a Category 2-equivalent hurricane on the Saffir–Simpson scale.[15] However, as it tracked northeastwards due to a trough embedded in the westerlies, it crossed into a region of high wind shear,[3] weakening into a severe cyclonic storm a few hours later.[16] Later that day, Hamoon made landfall south of Chittagong, Bangladesh as a severe tropical storm,[3] prompting the JTWC to stop tracking it.[17] Weakening rapidly once inland, on 12:00 UTC on 25 October, Hamoon degenerated into a well-marked low.[3] These remnants further weakened, last being monitored as a low-pressure area over northeastern India the next day.[18]

Preperations

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Bangladesh

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On 24 October, the Bangladesh Meteorological Department (BMD) issued Danger Signal No. 7 for the coastal districts of Barisal, Patuakhali, Bhola, Borguna, Pirojpur, Jhalokathi, Chittagong, Feni, Noakhali, Lakshmipur, and Chandpur, while advising the maritime ports of Payra and Chittagong to hoist Danger Signal No. 7 as well. Elsewhere, the maritime port of Cox's Bazar was advised to hoist Danger Signal No. 6, while the port of Mongla was advised to hoist Danger Signal No. 5.[19] Meanwhile, the Bangladesh Inland Water Transport Authority (BIWTA) halted all river traffic in the nation.[20] The Chittagong Port Authority dispatched 88 ships to the deep sea in order to safeguard against potential damages from Cyclone Hamoon.[21]

The government implemented measures to evacuate 1.5 million people from vulnerable areas, relocating them to government shelters across ten coastal districts in preparation for Cyclone Hamoon.[22] In St. Martin's Island, over 1,500 tourists were ordered to leave due to adverse weather conditions caused by Hamoon, being sent back to nearby Teknaf using three ships.[23] However, over 250 of these tourists disobeyed these orders.[24] Elsewhere, around 576 shelters in nine upazilas of Cox's Bazar District were activated.[24] In Barisal District, 541 cyclone response centers were established, alongside 61 medical teams and 322 tonnes of rice. Elsewhere, in Lakshmipur District, 285 shelters were arranged by the district's administration. Ships on the Lakshmipur-Bhola-Barishal route and ferries on the Lakshmipur-Bhola route were suspended. In Chittagong District, 803 shelters were opened as around 8,800 volunteers and 290 medical teams being readied. By 24 October, over 500 people were staying in shelters.[25]

Elsewhere

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As Hamoon developed into a deep depression on 23 October, the IMD issued a yellow warning in Odisha, for the districts of Bhadrak, Kendrapara, and Jagatsinghpur.[26] This was later expanded to include coastal districts in West Bengal.[27] Early the next day, they issued a rainfall alert for Odisha, West Bengal, Manipur, Tripura, Mizoram, Assam, and Meghalaya. Additionally, fishers planning to venture in and offshore Odisha, West Bengal, Bangladesh, and the northern coast of Myanmar were discouraged by the IMD.[28] In Pamban Island, a storm warning was issued to prevent fishers from leaving there.[29] All signals were lowered by 26 October.[30] Finally, in Myanmar, authorities in Rakhine State were issued an alert by the Department of Meteorology and Hydrology (DMH), being on standby and conducting preparedness tests.[31]

Impact

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Bangladesh

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In Cox's Bazar District, thousands of trees were uprooted while houses built with corrugated sheets were destroyed by Hamoon's winds. In the district's Rohingya refugee camps, hundreds of tarpaulin-covered bamboo shanties suffered damage.[32] Almost 470,000 people were affected as Hamoon made landfall, with 2,500 of them being Rohingya refugees. 800 of the refugees were temporarily displaced. Most of the learning centres run by Agrajattra sustained significant damage.[33] Elsewhere in the district, 500 people were displaced. In total, three people were killed while 63 people were injured in the district.[34]

As Hamoon made landfall, gusts from the cyclone disrupted the power supply to the city of Cox's Bazar, causing blackouts. A peak gust of 148 km/h (92 mph) was recorded in the city at 8:12pm local time, causing many houses and rice paddy fields to be levelled by intense winds.[35] Around 6 million lost power due to Hamoon.[36] Cox's Bazar recorded 71 mm (2.8 in) of rainfall.[35] In Chittagong District, one person died when they were crushed by a falling tree while another died when a building collapsed.[37] Teknaf recorded 87 mm (3.4 in) of rainfall in a day[35] while the city of Chittagong recorded 59 mm (2.3 in) in a day.[36] In Cox's Bazar district, 354 electricity poles were uprooted, 23 transformers were damaged and 496 electric wires were snapped. Collapsing trees caused the power supply to snap in over 800 places as they collapsed on electric wires.[38] In total, according to Aon, Hamoon caused around $250 million in damages.[1]

Elsewhere

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In India, due to Hamoon, the onset of the northeast monsoon would be delayed, causing India to, at the time, have a yearly rainfall deficit of 11%.[39] Portions of Odisha received light to moderate rainfall, with a peak of 52 mm (2.0 in) recorded in Paradeep.[40] Due to Hamoon's winds, air pollutants would be dispersed towards Chennai, causing the city to have a "moderate" air quality index.[41] The remnants of Hamoon later tracked into Myammar, producing heavy rain which peaked with 3.94 in (100 mm) in Thilin City and 2.95 in (75 mm) in Yangon.[42] In Thantlang Township, ten houses in the Bong Kwar IDP Camp suffered damage.[43]

Notes

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  1. ^ The name, a Persian word referring to inland desert lakes or marshlands, was suggested by Iran. These lakes are natural seasonal reservoirs in areas adjoining the Helmand basin.[2]

References

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  1. ^ a b 2024 Climate and Catastrophe Insight (PDF) (Report). Aon. 2024. p. 96. Retrieved 8 September 2024.
  2. ^ "How did Cyclone Hamoon get its name?". The Business Standard. 24 October 2023. Archived from the original on 29 December 2023. Retrieved 24 October 2023.
  3. ^ a b c d e f g Extremely Severe Cyclonic Storm 'HAMOON' over the Bay of Bengal (21st - 25th October, 2023): A Report (PDF) (Report). New Delhi, India: India Meteorological Department (Cyclone Warning Division). 11 June 2024. Retrieved 7 September 2024.
  4. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 17 October 2023. Retrieved 7 September 2024.
  5. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 20 October 2023. Retrieved 7 September 2024.
  6. ^ Significant Tropical Weather Advisory for the Indian Ocean, 1420Z 20 October 2023 (Report). United States Joint Typhoon Warning Center. 20 October 2023. Retrieved 7 September 2024.
  7. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 21 October 2023. Retrieved 7 September 2024.
  8. ^ Significant Tropical Weather Advisory for the Indian Ocean, 1800Z 21 October 2023 (Report). United States Joint Typhoon Warning Center. 21 October 2023. Retrieved 7 September 2024.
  9. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 21 October 2023. Retrieved 7 September 2024.
  10. ^ Tropical Cyclone Formation Alert (Invest 92B) (Report). United States Joint Typhoon Warning Center. 22 October 2023. Retrieved 7 September 2024.
  11. ^ Tropical Cyclone 06B (Six) Warning No. 1 (Report). United States Joint Typhoon Warning Center. 23 October 2023. Retrieved 7 September 2024.
  12. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 23 October 2023. Retrieved 7 September 2024.
  13. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 24 October 2023. Retrieved 7 September 2024.
  14. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 24 October 2023. Retrieved 7 September 2024.
  15. ^ Joint Typhoon Warning Center. Cyclone 06B (Hamoon) Best Track Data (Report). National Oceanic and Atmospheric Administration. Retrieved 7 September 2024.
  16. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 24 October 2023. Retrieved 7 September 2024.
  17. ^ Tropical Cyclone 06B (Six) Warning No. 7 (Report). United States Joint Typhoon Warning Center. 23 October 2023. Retrieved 7 September 2024.
  18. ^ Tropical Weather Outlook (PDF) (Report). New Delhi, India: India Meteorological Department. 26 October 2023. Retrieved 7 September 2024.
  19. ^ "Chittagong, Payra ports advised to hoist signal No 7". Prothomalo. 24 October 2023. Retrieved 8 September 2024.
  20. ^ "BIWTA halts all river traffic as Cyclone Hamoon approaches". bdnews24.com. 24 October 2023. Retrieved 8 September 2024.
  21. ^ "88 ships set sail for deep sea to dodge potential damage from Cyclone Hamoon". The Business Standard. 24 October 2023. Retrieved 24 October 2023.
  22. ^ "Bangladesh evacuating 1.5M people as Cyclone Hamoon approaches". Andolou Agency. Retrieved 24 October 2023.
  23. ^ Shishir, Joynal Abedin (23 October 2023). "Cyclone 'Hamoon' likely to make landfall Wednesday, signal 4". The Business Standard. Retrieved 8 September 2024.
  24. ^ a b "Cyclone Hamoon: Tourists defy directive on not going to beach in Cox's Bazar". The Business Standard. 24 October 2023. Retrieved 8 September 2024.
  25. ^ "Southern districts on alert to tackle Cyclone Hamoon". The Business Standard. 24 October 2023. Retrieved 8 September 2024.
  26. ^ Sharma, Vikash (23 October 2023). "Cyclone Hamoon to form over Bay of Bengal today; check IMD's district-wise rain forecast for Odisha". Odishatv.in. Retrieved 8 September 2024.
  27. ^ "Cyclone Hamoon may intensify in next 12 hours, IMD issues yellow alert for THESE states". mint. 23 October 2023. Retrieved 8 September 2024.
  28. ^ "Cyclone 'Hamoon' now turns into very severe cyclonic storm, 7 states on alert". India Today. 24 October 2023. Retrieved 8 September 2024.
  29. ^ "Cyclone Hamoon: IMD Says Landfall Process Begins, Seven States on High Alert | What We Know So Far". india.com. Retrieved 8 September 2024.
  30. ^ "Cyclone Hamoon: Maritime ports asked to lower cautionary signal". The Business Standard. 25 October 2023. Retrieved 8 September 2024.
  31. ^ "Tropical Cyclone HAMOON Myanmar Flash Update #1 (24 Oct 2023, 1300 HRS UTC +7) - Myanmar | ReliefWeb". ReliefWeb. 24 October 2023. Retrieved 8 September 2024.
  32. ^ "Cyclone Hamoon leaves destruction in Bangladesh". Yahoo News. Reuters. 25 October 2023. Retrieved 8 September 2024.
  33. ^ "Bangladesh: Cyclone Hamoon ravages Cox's Bazar as a severe cyclonic storm, affecting over 450,000 lives and damaging 13 IRC learning centres | International Rescue Committee (IRC)". Rescue.org. Retrieved 8 September 2024.
  34. ^ "3 killed, over 60 injured as Cyclone Hamoon crosses Bangladesh's coastal belt". Anadolu Agency. 25 October 2023. Retrieved 8 September 2024.
  35. ^ a b c Hossain, Emran; Islam, Nurul (24 October 2023). "Cyclone Hamoon hits with heavy wind on Bangladesh coast". New Age. Retrieved 8 September 2024.
  36. ^ a b Hossain, Emran; Islam, Nurul (25 October 2023). "Five killed as Hamoon brings misery to millions in Bangladesh". New Age. Retrieved 8 September 2024.
  37. ^ AFP; Hossain, Emran (26 October 2023). "Five dead, nearly 275,000 flee Bangladesh cyclone". Union of Catholic Asian News. Retrieved 8 September 2024.
  38. ^ Aziz, Abdul (26 October 2023). "Cyclone Hamoon leaves thousands in Cox's Bazar without power, fresh water". Dhaka Tribune. Retrieved 9 September 2024.
  39. ^ Agarwal, Ayushi (25 October 2023). "Cyclone Hamoon disrupts weather, delays Northeast Monsoon onset in India: Skymet - CNBC TV18". CNBC TV-18. Retrieved 9 September 2024.
  40. ^ "Cyclone Hamoon has weakened, now lies as depression over south of Mizoram: IMD". The Economic Times. 26 October 2023. Retrieved 9 September 2024.
  41. ^ "Cyclone Hamoon increases air pollution in Chennai". DT NEXT. 26 October 2023.
  42. ^ ""ဟမွန်း" ဆိုင်ကလုန်းမုန်တိုင်း မီဇိုရမ်ပြည်နယ်ကို မုန်တိုင်းငယ်အဖြစ် အားလျော့ ဝင်ရောက်" (in Burmese). DVB. 25 October 2023. Retrieved 8 September 2024.
  43. ^ "IDP camp in Chin State's Thantalang devastated by Cyclone Hamoon". mizzima. 31 October 2023. Retrieved 8 September 2024.
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