2017–18 South-West Indian Ocean cyclone season

The 2017–18 South-West Indian Ocean cyclone season was a below-average season that produced only 8 tropical storms, of which 6 became tropical cyclones. It was an event in the annual cycle of tropical cyclone and subtropical cyclone formation. It officially began on November 15, 2017, and officially ended on May 15, 2018, in Mauritius and the Seychelles. For the rest of the basin, the season ended on April 30, 2018. These dates conventionally delimit the period of each year when most tropical and subtropical cyclones form in the basin, which is west of 90°E and south of the Equator. Tropical and subtropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in La Réunion.

2017–18 South-West Indian Ocean cyclone season
Season summary map
Seasonal boundaries
First system formedDecember 27, 2017
Last system dissipatedMay 1, 2018
Strongest storm
NameBerguitta[nb 1]
 • Maximum winds165 km/h (105 mph)
(10-minute sustained)
 • Lowest pressure940 hPa (mbar)
Seasonal statistics
Total disturbances9 official, 1 unofficial
Total depressions9
Total storms8
Tropical cyclones6
Intense tropical cyclones3
Very intense tropical cyclones0
Total fatalities108 total
Total damage$63.9 million (2018 USD)
Related articles

Seasonal summary
Cyclone Ava

The season started with Tropical Depression 01U which was designated by the BOM, entered the basin on August 8 however quickly dissipated overseas. After a three month gap another low formed off the coast of Madagascar on December 27 which intensified into Tropical Cyclone Ava. It caused powerful winds upto 190 km/h (120 mph), caused extensive damage Toamasina and heavy downpour triggered flash flooding Tamatave and Antananarivo. After that another low formed on the Australian region and entered the basin. It was named Irving by the Bureau of Meteorology and peaked as a powerful Category 2 equivalent tropical cyclone. It dissipated off the coast of Madagascar. A day later after Ava and Irving, a low pressure formed near Mauritius and explosively intensified into a powerful Category 3 equivalent tropical cyclone named Berguitta. It passed near Mauritius and strong winds affected the textile industry, it then passed 50 km (31 mi) southeast of Réuníon and strong winds knocked down power lines and trees and left 72,000 people without power. Following with Berguitta, a tropical depression formed northeast of Madagascar and caused heavy downpours.

Five days after Berguitta dissipation, another tropical depression formed on January 25, it then peaked as a very powerful Category 4 equivalent tropical cyclone named Cebile. A month after Cebile, a tropical depression formed near the coast of Madagascar which then named as Dumazile. It peaked as a Category 3 equivalent tropical cyclone and caused agricultural damage in Reunion Island. Week after Dumazile dissipation, another low pressure formed off the east coast of Madagascar. It caused heavy downpours which destroyed 260 homes and flash flooding caused additional 630 homes destroyed; its remnants affected Reunion. Month later, Fakir formed east of Réuníon and dumped 415 mm (16.3 in) of rainfall which triggered landslides and took two people's lives. The season ended with Flamboyan which was the first system to be named by TCWC Jarkata, it peaked as Category 1 equivalent tropical cyclone and dissipated on May 1 without making landfall.

Systems

Tropical Cyclone Ava
Tropical cyclone (MFR)
Category 2 tropical cyclone (SSHWS)
 
DurationDecember 27 – January 9
Peak intensity155 km/h (100 mph) (10-min)  965 hPa (mbar)
Main article: Cyclone Ava

Ava formed on December 27 and dissipated on January 9.

The cyclone's powerful winds which were estimated at 190 km/h (120 mph) caused extensive damage in and around Toamasina.[1] Hundreds of power poles were snapped across Toamasina; Jirama estimated repairs to be in excess of 15 billion Ariary (US$4.62 million).[2] Heavy rains triggered flash floods in Tamatave and Antananarivo. Throughout Madagascar, at least 51 people died while 22 more were listed as missing.[1] Approximately 161,000 people suffered direct impacts from the cyclone,[3] with 54,000 people left homeless.[1]

Tropical Cyclone Irving
Tropical cyclone (MFR)
Category 2 tropical cyclone (SSHWS)
 
DurationJanuary 6 (Entered basin) – January 9
Peak intensity150 km/h (90 mph) (10-min)  964 hPa (mbar)

Tropical Cyclone Irving was named by the Bureau of Meteorology of Australia on January 6 as it crossed over into to the South-West Indian Ocean basin a few hours later. It strengthened to an equivalent of a Category 2 cyclone, before weakening as it turned southwestwards. It was last mentioned on 9th of January as it dissipated to the west of Madagascar. It stayed well from land.

Intense Tropical Cyclone Berguitta
Intense tropical cyclone (MFR)
Category 3 tropical cyclone (SSHWS)
 
DurationJanuary 9 – January 20
Peak intensity165 km/h (105 mph) (10-min)  940 hPa (mbar)

Berguitta formed on January 9 and dissipated on January 20.

On January 18, Berguitta passed just southeast of Mauritius, bringing strong winds and heavy rains. The textile sector suffered a loss of Rs200 million (US$6.08 million).[4] Later, Berguitta passed about 50 km (31 mi) southeast of Réunion,[5] with strong winds knocking down trees and left over 72,000 people without power.[6] A person was killed during the storm, and the agricultural loss of the island were at €16.7 million (US$20.4 million).[7][8]

Tropical Depression 04
Tropical depression (MFR)
 
DurationJanuary 14 – January 16
Peak intensity55 km/h (35 mph) (10-min)  999 hPa (mbar)

The depression formed on January 14 and dissipated on January 16.

The depression formed over the Mozambique Channel before making landfall on Mozambique. Its remnants reemerged over the Mozambique Channel before moving over Madagascar. The depression regenerated after reemerging into the ocean before dissipating northeast of Madagascar.

Intense Tropical Cyclone Cebile
Intense tropical cyclone (MFR)
Category 4 tropical cyclone (SSHWS)
 
DurationJanuary 25 – February 4
Peak intensity185 km/h (115 mph) (10-min)  944 hPa (mbar)

Cebile formed on January 25 and dissipated on February 4. A long-lived cyclone, it erratically moved to the west, then to the south, then to the east, to the south, to the southeast, then to the south again, to the west, when it started to become extratropical. It was last noted on 4th of February as it merged with another extratropical cyclone to its south. It peaked as an Intense Tropical Cyclone, or equivalent to a strong Category 4 cyclone. It stayed well away from land.

Intense Tropical Cyclone Dumazile
Intense tropical cyclone (MFR)
Category 3 tropical cyclone (SSHWS)
 
DurationMarch 1 – March 6
Peak intensity165 km/h (105 mph) (10-min)  945 hPa (mbar)

Dumazile formed from a low on March 2. After formation, Dumazile began rounding a subtropical ridge to the east. Dumazile brought heavy rain to Madagascar.[9] Dumazile then began weakening as a result of increasing shear wind from a low pressure system to the southwest and became post-tropical early on March 7.

Dumazile produced flooding rainfall and gusty winds on Réunion.[10] Agricultural damage on the island reached €3 million (US$3.73 million)[11]

Severe Tropical Storm Eliakim
Severe tropical storm (MFR)
Category 1 tropical cyclone (SSHWS)
 
DurationMarch 13 – March 20
Peak intensity110 km/h (70 mph) (10-min)  980 hPa (mbar)

At least 21 people were killed and approximately 19,000 people were affected in Madagascar.[12] The eastern coastal districts were the hardest hit. More than 260 homes were destroyed and a further 630 were flooded.[13] Road damages were about 12 billion ariary (US$3.85 million).[14]

High waves from Eliakim affected coastal roads in Réunion, and wind gusts reached 151 km/h (94 mph) on the island.[15]

Tropical Cyclone Fakir
Tropical cyclone (MFR)
Category 1 tropical cyclone (SSHWS)
 
DurationApril 20 – April 24
Peak intensity130 km/h (80 mph) (10-min)  975 hPa (mbar)

On April 24, Fakir passed quickly just east of Réunion. A late-season storm, Fakir dropped 415 mm (16.3 in) of rainfall in a 24-hour period, as well as producing 176 km/h (109 mph) wind gusts. The heavy rainfall caused flooding and landslides.[16] Two people died due to mudslides, and the economic loss were about €20 million (US$24.5 million).[17][18]

Severe Tropical Storm Flamboyan
Severe tropical storm (MFR)
Category 1 tropical cyclone (SSHWS)
 
DurationApril 28 (Entered basin) – May 1
Peak intensity110 km/h (70 mph) (10-min)  983 hPa (mbar)

Late on April 28, Flamboyan entered the South-West Indian Ocean basin as a developing Category 1 cyclone. Flamboyan retained its name after moving into the basin, becoming the first moderate tropical storm in the South-West Indian Ocean basin to be named by TCWC Jakarta in history.[nb 2] On April 29, Flamboyan intensified into a severe tropical storm before gradually weakened. It was last mentioned on May 1.

Other systems

The first disturbance of this season, a low-pressure system, classified as a tropical low by the Australian Bureau of Meteorology,[19] moved west-southwestward across the 90th meridian east into the South-West Indian Ocean basin on August 8.[20] At 10:00 UTC on the following day, Météo-France Réunion upgraded the low-pressure system to a zone of disturbed weather, with sustained winds of up to 55 km/h (35 mph) being detected on the southern side of the circulation by scatterometer.[21] At this time, the disturbance was located approximately 2,375 km (1,475 mi) west of Jakarta, Indonesia.[21] Météo-France noted that the revival of convective activity in the basin was likely due to the interaction between an eastward-moving Kelvin wave and a westward-moving Rossby wave.[21]

Storm names

Within the South-West Indian Ocean, tropical depressions and subtropical depressions that are judged to have 10-minute sustained wind speeds of 65 km/h (40 mph) by the Regional Specialized Meteorological Center on La Réunion Island, France (RSMC La Réunion) are usually assigned a name. However, it is the Sub-Regional Tropical Cyclone Advisory Centers in Mauritius and Madagascar who name the systems. The Sub-Regional Tropical Cyclone Advisory Center in Mauritius names a storm should it intensify into a moderate tropical storm between 55°E and 90°E. If instead a cyclone intensifies into a moderate tropical storm between 30°E and 55°E then the Sub-Regional Tropical Cyclone Advisory Center in Madagascar assigns the appropriate name to the storm. Beginning from the 2016–17 season, name lists within the South-West Indian Ocean will be rotated on a triennial basis. Storm names are only used once, so any storm name used this year will be removed from rotation and replaced with a new name for the 2020–21 season. The unused names are expected to be reused in the list for the 2020–21 season.[22]

  • Ava
  • Berguitta
  • Cebile
  • Dumazile
  • Eliakim
  • Fakir
  • Guambe (unused)
  • Habana (unused)
  • Iman (unused)
  • Jobo (unused)
  • Kanga (unused)
  • Ludzi (unused)
  • Melina (unused)
  • Nathan (unused)
  • Onias (unused)
  • Pelagie (unused)
  • Quamar (unused)
  • Rita (unused)
  • Solani (unused)
  • Tarik (unused)
  • Urilia (unused)
  • Vuyane (unused)
  • Wagner (unused)
  • Xusa (unused)
  • Yarona (unused)
  • Zacarias (unused)

After the season, those six names used were automatically retired and were replaced with Alicia, Bongoyo, Chalane, Danilo, Eloise and Faraji, respectively for the 2020–21 season.

Seasonal effects

This table lists all of the tropical cyclones and subtropical cyclones that were monitored during the 2017–2018 South-West Indian Ocean cyclone season. Information on their intensity, duration, name, areas affected, primarily comes from RSMC La Réunion. Death and damage reports come from either press reports or the relevant national disaster management agency while the damage totals are given in 2017 or 2018 USD.

Name Dates active Peak classification Sustained
wind speeds		 Pressure Areas affected Damage
(USD)		 Deaths Refs
AvaDecember 27 – January 9Tropical cyclone155 km/h (100 mph)965 hPa (28.50 inHg)Madagascar$4.62 million73[23][24]
IrvingJanuary 6 – 9Tropical cyclone150 km/h (90 mph)964 hPa (28.47 inHg)NoneNoneNone
BerguittaJanuary 9 – 20Intense tropical cyclone165 km/h (105 mph)940 hPa (27.76 inHg)Mauritius, Réunion$26.5 million1[25][24]
04January 14 – 16Tropical depression55 km/h (35 mph)999 hPa (29.50 inHg)Madagascar, Mozambique$5.1 million11[24]
CebileJanuary 25 – February 4Intense tropical cyclone185 km/h (115 mph)944 hPa (27.88 inHg)NoneNoneNone
DumazileMarch 1 – 6Intense tropical cyclone165 km/h (105 mph)945 hPa (27.91 inHg)Madagascar, Réunion$3.73 millionNone
EliakimMarch 13 – 20Severe tropical storm110 km/h (70 mph)980 hPa (28.94 inHg)Madagascar$3.85 million21[26][27]
FakirApril 20 – 24Tropical cyclone130 km/h (80 mph)975 hPa (28.79 inHg)Madagascar, Réunion, Mauritius$24.5 million2[28][29]
FlamboyanApril 28 – May 1Severe tropical storm110 km/h (70 mph)983 hPa (29.03 inHg)NoneNoneNone
Season aggregates
9 systemsDecember 27 – May 1185 km/h (115 mph)940 hPa (27.76 inHg)$63.9 million108

See also

Footnotes
  1. The strongest winds were actually from Cebile, at 185 km/h (115 mph).
  2. Durga in April 2008 exited from this basin. Bakung in December 2014 entered as a remnant low.

References
  1. "Le bilan du cyclone Ava à Madagascar s'élève à 51 morts". Le Monde (in French). Agence France-Presse and Reuters. January 15, 2018. Retrieved February 1, 2018.
  2. "15 milliards ariary de perte" (in French). L'Express de Madagascar. January 16, 2018. Retrieved January 23, 2018.
  3. "Madagascar : le cyclone Ava a fait 51 morts et 22 disparus". Le Parisien (in French). January 15, 2018. Retrieved February 1, 2018.
  4. "Secteur textile: Rs 200 millions de pertes de revenus durant la période cyclonique" (in French). Mauritius business. January 23, 2018. Retrieved January 24, 2018.
  5. "Berguitta : levée de l'alerte cyclonique à La Réunion, recherche d'un "éventuel disparu"" (in French). Europe 1. January 19, 2018. Retrieved January 20, 2018.
  6. "Tropical Cyclone Berguitta PATH LIVE: Storm track LOOMS on La Reunion as Mauritius BLASTED". Daily Express. January 18, 2018. Retrieved January 19, 2018.
  7. Jean Marie Gangaram (January 19, 2018). "Chute fatale de Gérard Nayna : Le cyclone Berguitta fait un mort" (in French). 5-Plus Dimanche. Retrieved January 20, 2018.
  8. Manuel Yepes (January 23, 2018). "Berguitta : plus de 16 millions d'euros de pertes agricoles" (in French). 5-Plus Dimanche. Retrieved January 24, 2018.
  9. "Madagascar – Heavy Rain Reported as Tropical Cyclone Dumazile Moves South".
  10. "Tropical Cyclone Dumazile Floods Roads on Reunion Island". The Daily Telegraph. Retrieved January 2, 2019.
  11. @Clicanoore (March 12, 2018). "#Dumazile : les pertes chiffrées à 3 millions d'euros" (Tweet) – via Twitter.
  12. "La tempête Eliakim fait 21 morts" (in French). Les Décrypteurs. March 23, 2018. Retrieved March 24, 2018.
  13. "17 die in Madagascar tropical storm". Daily Nation. March 19, 2018. Retrieved March 19, 2018.
  14. "Argent dérobé au PM Mahafaly : le montant exact estimé en fait à 12 milliards Ar" (in French). La Gazette de la Grande Ile. April 7, 2018. Retrieved April 10, 2018.
  15. "Eliakim - La Réunion en vigilance forts vents et forte houle" (in French). Imaz Press Réunion. March 19, 2018. Retrieved January 2, 2019.
  16. "Réunion : forte tempête tropicale Fakir". Meteo-France. April 24, 2018. Retrieved January 2, 2019.
  17. "La Réunion. Tempête tropicale Fakir : deux morts dans une coulée de boue" (in French). Ouest-France. April 24, 2018. Retrieved January 2, 2019.
  18. "Fakir : la facture va dépasser 20 millions d'euros" (in French). Clicanoo. May 15, 2018. Retrieved January 2, 2019.
  19. "WebCite query result". www.webcitation.org. Archived from the original on August 8, 2017. Retrieved August 8, 2017.
  20. "WebCite query result". www.webcitation.org. Archived from the original on August 8, 2017. Retrieved August 9, 2017.
  21. "ZCIT Bulletin for August 9 2017" (PDF).
  22. Regional Association I Tropical Cyclone Committee (2016). "Tropical Cyclone Operational Plan for the South-West Indian Ocean" (PDF). World Meteorological Organization. Retrieved October 5, 2016.
  23. Ny Aina Rahaga (January 23, 2018). "10 milliards d'Ariary pour le rétablissement de l'électricité après le cyclone AVA" (in French). Madagascar Tribune. Retrieved February 1, 2018.
  24. "Global Catastrophe Recap January 2018" (PDF). thoughtleadership.aonbenfield.com. Aon Benfield. Retrieved February 10, 2018.
  25. "Tempête tropicale intense : quel impact et quel coût sur les secteurs affectés ?". Le Défi Média. January 19, 2018. Retrieved January 19, 2018.
  26. "Dozens Deaths Confirm Malagasy's Fear of Cyclone". Prensa Latina. March 20, 2018. Retrieved March 21, 2018.
  27. "Global Catastrophe Recap March 2018" (PDF). thoughtleadership.aonbenfield.com. Aon Benfield. Retrieved April 23, 2018.
  28. "Tropical Storm Fakir turns deadly after unleashing destructive winds, mudslides on La Reunion". AccuWeather. April 26, 2018. Retrieved April 27, 2018.
  29. "Global Catastrophe Recap April 2018" (PDF). thoughtleadership.aonbenfield.com. Aon Benfield. Retrieved May 17, 2018.
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