Cyclone Roanu

Cyclonic Storm Roanu[nb 1] was a relatively weak tropical cyclone that caused severe flooding in Sri Lanka and Bangladesh during May 2016. It is the first tropical cyclone of the annual cyclone season. Roanu originated from a low-pressure area that formed south of Sri Lanka, which gradually drifted north and intensified into a cyclonic storm on 19 May. However, wind shear and land interaction caused it to weaken slightly, before reintensifying as it accelerated towards the coast of Bangladesh.

Cyclonic Storm Roanu
Cyclonic storm (IMD scale)
Tropical Storm (SSHWS)
Roanu 2016-05-21 0450Z.jpg
Cyclone Roanu at peak intensity, approaching Bangladesh on 21 May
Formed19 May 2016
Dissipated23 May 2016
(Remnant low after 22 May)
Highest winds3-minute sustained: 85 km/h (50 mph)
1-minute sustained: 110 km/h (70 mph)
Lowest pressure983 hPa (mbar); 29.03 inHg
Fatalities135 total, 99 missing
Damage$2.13 billion (2016 USD)
Areas affectedSri Lanka, East coast of India, Bangladesh, Myanmar, Yunnan
Part of the 2016 North Indian Ocean cyclone season

The storm was responsible for 201 deaths in Sri Lanka and another 26 deaths in Bangladesh. Damage throughout Sri Lanka reached US$2 billion. Roanu also brought torrential rainfall to the Indian states of Tamil Nadu, Andhra Pradesh, Kerala and Odisha as it drifted in a generally northeastward direction, close to the coast.

Meteorological historyEdit

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)
Storm type
  Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

Under the influence of a trough, a low-pressure area formed over the Bay of Bengal on 14 May.[2][3] It slowly consolidated as it paralleled the east coast of Sri Lanka, prompting the India Meteorological Department (IMD) to classify it as a depression on 17 May.[4] Late the same day, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert (TCFA), soon after which the JTWC upgraded the system to a tropical storm.[5][6] Simultaneously, the IMD upgraded the storm to a Deep Depression, prompting the issuance of cyclone warnings for the states of Andhra Pradesh and Odisha.[7] On 19 May, the IMD reported that the storm had reached cyclonic storm intensity, and assigned it the name Roanu.[8]

At the time, Roanu was tracking slowly northward along the northern periphery of a subtropical ridge located over the Malay Peninsula. Despite favorable outflow and warm sea surface temperatures (SSTs) reaching 31 °C (88 °F), its proximity to land and moderate vertical wind shear kept the storm from intensifying rapidly.[9] The diurnal temperature variation over land and the persistent wind shear began to affect the deep convection obscuring the low-level circulation center (LLCC). In the late hours of that day, Roanu showed a weakening trend after most of the convection covering the LLCC was sheared off. During that time, Roanu was located approximately 150 kilometres (93 mi) from Visakhapatnam. However, the wind shear soon decreased,[10] and the storm reestablished deep convection over and around the LLCC, forming a central dense overcast in a period of 6 hours. SSMIS imagery revealed tightly curved rainbands wrapped into the LLCC.[11] As a result, Roanu re-intensified as it accelerated east-northeastwards towards the coast of Bangladesh,[12] and reached its peak intensity with winds of 85 km/h (55 mph) and a minimum central pressure of 983 hPa (mbar; 29.03 inHg).[13] On 21 May, Roanu made landfall just northwest of Chittagong, Bangladesh.[14] Continuing to accelerate inland, Roanu steadily weakened and degenerated into a remnant low on the next day.[citation needed]

Preparations and impactEdit

Deaths and damage by countries
Countries Fatalities Missing Damage
(2016 USD)
Sri Lanka 105 99 $2 billion [15][16]
India None None Minimal
Bangladesh 30 None $127 million [17][18]
Totals: 135 99 $2.13 billion

Sri LankaEdit

The precursor to Cyclone Roanu over Sri Lanka on 15 May.

Preparations for the storm began even before the IMD started tracking it as a depression. As the area of low pressure tracked closer to the country, the Meteorology Department of Sri Lanka issued a warning on 13 May stating that the disturbance would affect the country. Fishermen were advised to be vigilant.[19] Later, The National Building Research Organisation (NBRO) issued landslide warning in the districts of Badulla, Monaragala, Kandy, Ratnapura, Kurunegala, Nuwara Eliya, Kegalle and Matale.[20] President Maithripala Sirisena instructed the local authorities to provide relief to those affected by the system. The Minister Of Disaster Management, Defense Secretary, Tri Forces' Commanders and the Inspector General Of Police were instructed to undertake the operation.[21]

Sri Lankan Disaster Management Centre (DMC) issued a flood alert on 16 May as the low-pressure area brought heavy rains to the country. The Kelani River and Maha Oya swelled as a result of the rainfall.[22] The depression brought torrential rains to Sri Lanka, causing flash flooding and landslides, resulting in 37 deaths. Additionally, the storm displaced over 134,000 people.[23] By 26 May, the death toll had risen to 104, while 99 people had been reported missing.[16] The Sri Lankan Disaster Management Centre said that areas of the nation received the highest amount of rainfall since 2010. Landslides buried three villages in Kegalle District.[24]

Damage throughout Sri Lanka reached US$2 billion.[16]


Parts of Chennai and Tamil Nadu received between 93 mm (3.7 in) and 116.0 mm (4.57 in) of rain in a period of 24 hours.[25] Kelambakkam, Chennai, received 226 mm of rainfall on 19 May.[26] Later reports indicated that the city had received the highest rainfall in the month of May in over 2 decades.[27] 12,000 personnel were deployed in the city to aid rescue operations. Multiple boats were stationed around the city for emergency rescue. In the low-lying areas, the National Disaster Response Force positioned 4 teams of personnel. An emergency number (1070) was set up.[28] The IMD put the states of Andhra Pradesh and Odisha on an orange alert (the second highest level of emergency in India) on 19 May. The city of Kakinada recorded 174 mm (6.9 in) of rain in a day, the highest reported in the past 10 years. Bapatla reported 134 mm (5.3 in) of rain. Visakhapatnam District, Vizianagaram District and Srikakulam District were also affected by rains and were forecast to receive up to 210 mm (8.3 in) by 21 May.[29] Chief Minister of Andhra Pradesh N. Chandrababu Naidu positioned 5 teams, each consisting of 100 personnel, in Krishna, East Godavari and Visakhapatnam districts.[30]

Under the influence of the system, various places in Odisha received moderate to heavy rainfall. The reported rainfall was 96 mm (3.8 in) in Paradip and 85 mm (3.3 in) in Puri. Chief Minister of Odisha Naveen Patnaik readied 10 teams of Odisha Disaster Rapid Action Force and fire service personnel. Government of Odisha issued an alert in at least 12 districts in coastal, southern and northern regions of the state. The maximum temperature in Bhubaneshwar on 20 May was 26.2 °C (79.2 °F)[31] compared to the average daily maximum temperature of 37.2 °C (99.0 °F) for the month of May.[32] In West Bengal, Digha received 73 mm (2.9 in) of rainfall and Sagar Island received 96 mm (3.8 in) as the cyclone inched closer.[33]


An animation depicting Roanu nearing landfall over Bangladesh.

Before the cyclone made landfall, over half a million people had been taken into shelters by the Government of Bangladesh.[34] All flights at Shah Amanat International Airport were suspended. Restrictions were imposed on the movement of ships and ferries by Bangladesh Inland Water Transport Authority.[35]

A storm surge up to 7 ft (2.0 m) above the astronomical tide hit the coast of Bangladesh at afternoon.[35] The cyclone approached the land over the coast at Sandwip, Hatia, Kutubdia, Sitakundu and Feni.[36] The cyclone caused at least 26 deaths in seven districts across the country.[37] 30 people died when Roanu hit the county, most of them died when the cyclone's storm surge overtopped dams.[17] Around 40,000 homesteads and business houses were damaged.[38]

The storm disrupted electricity supply and road communications in the areas.[39] Food storage, seasonal crops were damaged. Livestock, including fish and shrimp firms were swept away.[40] Damage across the nation were estimated at 10 billion (US$127 million).[18]


Sri LankaEdit

Rescue operations began soon after the storm, on 18 May, with Sri Lankan military personnel searching for missing people in rural areas. 115 soldiers reportedly searched the villages buried by the landslides in attempt to find any survivors.[41] At least 50 people were rescued from the hardest-hit areas in the Kegalle District.[42] However, another spell of heavy rain on 19 May disrupted the operations. Mud in some villages was reportedly as high as 75 ft (23 m).[43] Major General Sudantha Ranasinghe, the officer in charge of the rescue operation, later told that the authorities had begun to give up the rescue operations. The death toll was confirmed to be 58.[44] By the evening of 19 May, rescuers feared that the remaining 134 people missing were dead.[42] On 20 May, the Indian Navy Southern Naval Command sent its ships INS Sunayna and HMIS Sutlej with relief material to the capital city, Colombo.[45] Australian Minister for Foreign Affairs Julie Bishop pledged assistance to Sri Lanka, saying "The Australian Government stands ready to provide any assistance that our Sri Lankan friends may require in responding to this disaster."[46][47] Pakistan's Government also sent field hospital and relief materials.[48] As the search operations resumed that day, rescuers continued recovering bodies of those buried in the landslides which also reportedly destroyed 66 houses in Elangapitiya.[49] 200,000 people had to escape from the low-lying areas of Colombo on rubber dinghies and makeshift rafts. A total of 101 deaths and 100 missing persons have been reported.[50] The Sri Lanka national cricket team donated SL Rs. 1,000,000 (US$6,869) to the victims of Roanu.[51]

See alsoEdit


  1. ^ The name Roanu was contributed by the Maldives; it means [strong] in the Maldivian language.[1]


  1. ^ "Why is the cyclone called Roanu?". The Daily Star. 21 May 2016. Retrieved 23 May 2016.
  2. ^ "Tropical Weather Outlook" (PDF). India Meteorological Department. Archived from the original (PDF) on 5 March 2016. Retrieved 14 May 2016.
  3. ^ "All India Weather Summary and Forecast Bulletin, Night of 14 May 2016" (PDF). India Meteorological Department. Archived from the original (PDF) on 31 March 2016. Retrieved 14 May 2016.
  4. ^ Yadav, B. P. "Special Tropical Outlook for the North Indian Ocean issued at 0600 UTC of 17 May 2016" (PDF). India Meteorological Department. Archived from the original (PDF) on 5 March 2016. Retrieved 17 May 2016.
  5. ^ "Current Significant Tropical Weather Advisories ABIO10 (Indian Ocean) reissued at 18 May 2016, 0030 UTC". Joint Typhoon Warning Center. Archived from the original on 18 May 2016. Retrieved 18 May 2016.
  6. ^ "Tropical Cyclone 01B (One) Warning #01 Issued on 18 May 2016 at 0900 UTC". Joint Typhoon Warning Center. Archived from the original on 29 April 2016. Retrieved 18 May 2016.
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  8. ^ Kotal, S. D. "Cyclonic Storm Roanu, Bulletin No. 9 issued at 0300 UTC, 19 May 2016" (PDF). India Meteorological Department. Archived from the original (PDF) on 16 November 2015. Retrieved 19 May 2016.
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  10. ^ "Tropical Cyclone 01B (Roanu) Warning #07". Joint Typhoon Warning Centre. Archived from the original on 29 April 2016. Retrieved 19 May 2016.
  11. ^ "Tropical Cyclone 01B (Roanu) Warning #06". Joint Typhoon Warning Center. Archived from the original on 29 April 2016. Retrieved 19 May 2016.
  12. ^ "Tropical Cyclone 01B (Roanu) Warning #08". Joint Typhoon Warning Center. Archived from the original on 29 April 2016. Retrieved 20 May 2016.
  13. ^ Mohapatra, M. "Tropical Storm Roanu Advisory No. 17 issued at 0900 UTC of 21 May 2016" (PDF). India Meteorological Department. Archived from the original (PDF) on 23 May 2016. Retrieved 23 May 2016.
  14. ^ Mohapatra, M. "Tropical Storm Roanu Advisory No. 16 issued at 1500 UTC of 21 May 2016" (PDF). India Meteorological Department. Archived from the original (PDF) on 5 March 2016. Retrieved 21 May 2016.
  15. ^ Global Catastrophe Recap May 2016 (PDF) (Report). Aon Benfield. 8 June 2016. Retrieved 8 June 2016.
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  17. ^ a b Saleemul Huq (27 May 2016). "Cyclone Roanu hits Bangladesh: a story of loss and damage avoided". International Institute for Environment and Development. Retrieved 27 May 2016.
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  22. ^ "Sri Lanka on alert for floods, landslides". The Times of India. Retrieved 19 May 2016.
  23. ^ "12 die in Sri Lanka flash floods, several missing". Bennett, Coleman & Co. Ltd. (The Times of India). Retrieved 17 May 2016.
  24. ^ Perera, Amantha (18 May 2016). "200 families missing as Sri Lankan landslides bury three villages". The Guardian. Retrieved 18 May 2016.
  25. ^ Karthikeyan, Hemalatha (18 May 2016). "Depression moving away, but Chennai will continue to get rain on Wednesday". The Times of India. Retrieved 18 May 2016.
  26. ^ "Maalaimalar News: 226 mm rain in kelambakkam". 18 May 2016. Retrieved 23 May 2016.
  27. ^ Shekhar, Laasya (19 May 2016). "Chennai records 11.7cm of rainfall breaking a two-decade-old record". Deccan Chronicle. Retrieved 19 May 2016.
  28. ^ "Chennai rains: Authorities keep boats on standby after heavy rain". News Nation. Retrieved 19 May 2016.
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  30. ^ "Cyclone Roanu drops anchor off A.P." The Hindu. 19 May 2016. Retrieved 20 May 2016.
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  32. ^ "Bhubaneshwar Climate Normals 1971–1990". National Oceanic and Atmospheric Administration. Retrieved 24 December 2012.
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  35. ^ a b "Half a million flee as Cyclone Roanu hits Bangladesh". Aljazeera. Retrieved 22 May 2016.
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External linksEdit