The 2023–24 South-West Indian Ocean cyclone season is the current event of the annual cycle of tropical and subtropical cyclogenesis. It began on 15 November 2023, and will end on 30 April 2024, with the exception for Mauritius and the Seychelles, for which it will end on 15 May 2024. 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. However, tropical cyclones can form year-round, and all tropical cyclones that will form between 1 July 2023 and 30 June 2024 will be part of the season. Tropical and subtropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in Réunion and unofficially by the Joint Typhoon Warning Center.
| 2023–24 South-West Indian Ocean cyclone season | |
|---|---|
 Season summary map | |
| Seasonal boundaries | |
| First system formed | 30 December 2023 |
| Last system dissipated | Season ongoing |
| Strongest storm | |
| Name | Belal |
| • Maximum winds | 150 km/h (90 mph) (10-minute sustained) |
| • Lowest pressure | 966 hPa (mbar) |
| Seasonal statistics | |
| Total disturbances | 2 |
| Total depressions | 2 |
| Total storms | 2 |
| Tropical cyclones | 1 |
| Total fatalities | 20 total |
| Total damage | None |
| Related articles | |
Seasonal forecasts
| Records | Moderate Tropical Storms |
Very/Intense Tropical Cyclones | ||
|---|---|---|---|---|
| Record high: | 15 | 9 | ||
| Record low: | 3 | 0 | ||
| Systems | ||||
| Mauritius Meteorological Services | 6–8 tropical cyclones | |||
| Météo-France | 5–8 tropical cyclones | |||
| Forecast Center | Chance of above average | |||
| Météo-France | 10% | 20% | 70% | |
| Source: Seasonal Outlook for Tropical Cyclones.[1][2] | ||||
In October 2023, Météo-France issued its seasonal forecast of cyclone activity for the basin, predicting a below-average season with 5–8 moderate tropical storms due to an expected strong El Niño event. The MFR also stated that the chance for a below-average season was 70%. Average cyclone activity was given a 20% chance, while an above-average level of activity was given a 10% chance.[1]
The Mauritius Meteorological Services (MMS) also released their summer outlooks for the season, stating that around six to eight cyclones were expected to form, with the region west of Diego Garcia having environmental conditions more conducive for cyclogenesis.[2]
Seasonal summary
The season officially started on 15 November 2023, however the first system, Alvaro, would not form until 30 December. Alvaro became a tropical depression the next day, traversing the Mozambique Channel, before making landfall in Morombe District, Madagascar on 1 January 2024.[3] After a brief lull in activity, Tropical Cyclone Belal formed on 11 January.[4]
Systems
Severe Tropical Storm Alvaro
| Severe tropical storm (MFR) | |
| Tropical storm (SSHWS) | |
| Duration | 30 December – 3 January |
|---|---|
| Peak intensity | 110 km/h (70 mph) (10-min); 985 hPa (mbar) |
In December 2023, the MFR began to monitor the potential for tropical cyclogenesis as Kelvin waves and Rossby waves intersect in the western portion of the agency's area of responsibility, ahead of a wet phase of the Madden–Julian oscillation (MJO).[5] By 29 December, a monsoon trough had produced convection southeast of Beira, Mozambique that spun, as convergence of winds increases within the system's closed surface circulation.[6] The next day, the MFR classified the system as a tropical disturbance,[7] and in addition, the JTWC began monitoring the disturbance.[8] Tracking southeast under the influence of a ridge, the disturbance was further upgraded to a tropical depression by the MFR on December 31.[9] The warm core consolidated, causing the system to intensify into a moderate tropical storm and receive the name Alvaro.[10] Moreover, the JTWC designated the storm as Tropical Cyclone 04S.[11]
During 1 January 2024, Alvaro's maintenance of a curved band and the emergence of an eye prompted the MFR to upgrade the system to a severe tropical storm, as Alvaro continued to strengthen under favorable conditions despite vertical wind shear in the mid-level troposphere.[12] The storm grew a central dense overcast around its ragged, inchoate eye while 269 km (167 mi) east-northeast of Europa Island, continuing east-southeast.[13] Around 12:00 UTC, both the MFR and JTWC stated that Alvaro had peaked with sustained winds of 110 km/h (70 mph);[14][15] the MFR also measured the system's lowest barometric pressure at 985 hPa (29.09 inHg).[14] As the storm approached Madagascar, the cloud tops slowly eroded and warmed up, as the eye gradually disappeared due to persistent wind shear.[16] At 19:20 EAT (16:20 UTC) that day, Alvaro made landfall in Morombe District.[3] Alvaro rapidly weakened from the mountainous terrain of the island nation, with rainbands around the core no longer present.[17] By 12:00 UTC of 2 January, Alvaro weakened into an overland depression and exhibited the circulation to satellite imagery, only retaining convection over the east quadrant.[18] Alvaro re-entered the Indian Ocean on 3 January, re-intensifying back into a moderate tropical storm.[19] Shortly thereafter, Alvaro would succumb to strong wind shear as mid-level dry air invaded the storm, despite substantial outflow boosted by a subtropical jet.[20] By 18:00 UTC, the MFR classified Alvaro as a post-tropical depression after it had lost its tropical characteristics.[21] The MFR issued its final bulletin on Alvaro on 4 January, as the system interacted with the baroclinic zone.[22]
Anticipating Alvaro's landfall, the meteorological service of Madagascar (Meteo Madagascar) raised a yellow alert for the districts of Morondava, Manja, Morombe, and Toliara on 31 December,[23] which would be upgraded to a red alert a day later as Alvaro made landfall.[3] Mariners across Maintirano and Toliara were advised to stay out of sea.[23] The mayor of Morombe reported property damage. Several parts of the city were flooded, and many residents evacuated from their homes, using schools and outlying villages as accommodation sites.[24] Areas of southern Madagascar reported uprooted trees, torn roofs, and damaged infrastructure, necessitating international assistance.[25] Nearly 33,000 people in Madagascar were affected by Alvaro, with over 17,000 displaced. The regions of Haute Matsiatra, Atsimo-Andrefana, and Menabe suffered the brunt of the storm.[26] The displaced people were relocated to 36 evacuation centers. About 241 settlements were totally destroyed, and 426 homes were damaged in addition to 15 schools.[27] Nineteen people were killed by the storm.[26] In response to the disaster, the World Food Programme (WFP) allocated rice, oil, mosquito nets, and other equipment to the affected areas,[28] in cooperation with the United States Agency for International Development (USAID).[26]
Tropical Cyclone Belal
| |||
On 11 January, the MFR marked a zone of disturbed weather, citing the conducive conditions induced by the MJO and an equatorial Rossby wave. The monsoon trough north-northeast of Madagascar had intensified several days prior, as convergence transferred moisture aloft.[4] Concentration of convection near the center increased, particularly in the western section, as the system moved south.[29] By the next day, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) on the potential disturbance, since it was in an environment of very warm sea surface temperatures, high ocean heat content, low vertical shear, and excellent outflow.[30] At 12:00 UTC, the MFR categorized the system as a tropical depression. Additionally, microwave imagery indicated an eye in the lower-layer while the storm steered more westward,[31] and the JTWC began issuing advisories on the system as a tropical cyclone.[32] By 13 January, it intensified to a moderate tropical storm, prompting the MMS to name it Belal.[33] Intense lightning activity within the center further signaled a period of rapid intensification, leading to Belal becoming a severe tropical storm.[34] As the storm developed a well-defined eye, the MFR upgraded Belal to a tropical cyclone early on January 14.[35]
As the system developed, the MFR issued a yellow cyclone pre-alert for Réunion on 13 January,[36] which was upgraded to an orange cyclone alert on 15:00 UTC the next day.[37] On 13 January, the MMS issued a class I cyclone warning for Mauritius.[38] On 14 January, the MFR would upgrade its orange alert into a red alert for Réunion as Belal neared the nation.[39] The next day, the MFR would issue a purple alert for Réunion as Belal neared the coast.
Current storm information
For the latest official information, see:
- MFR's Cyclone Bulletin for Tropical Cyclone 2 (Belal)
- JTWC's Tropical Cyclone Warning for Tropical Cyclone Belal (05S)
Storm names
Within the South-West Indian Ocean, tropical and subtropical cyclones that are judged to have 10-minute sustained winds of 65 km/h (40 mph) by the Regional Specialized Meteorological Center on 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 (Mauritius Meteorological Services) in Mauritius names a storm if it intensifies 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 (Meteo Madagascar) in Madagascar assigns the appropriate name to the storm. Storm names are taken from three pre-determined lists of names, which rotate on a triennial basis, with any names that have been used automatically removed. New names this season are Alvaro, Belal, Candice, Djoungou, Eleanor, Filipo, Gamane, Hidaya, Ialy, and Jeremy which replaced Alicia, Bongoyo, Chalane, Danilo, Eloise, Faraji, Guambe, Habana, Iman, and Jobo which were used in the 2020–21 season.[40]
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Season effects
This table lists all of the tropical cyclones and subtropical cyclones that were monitored during the 2023–2024 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 2023 or 2024 USD.
| Name | Dates | Peak intensity | Areas affected | Damage (USD) |
Deaths | Refs | ||
|---|---|---|---|---|---|---|---|---|
| Category | Wind speed | Pressure | ||||||
| Alvaro | 30 December – 3 January | Severe tropical storm | 110 km/h (70 mph) | 985 hPa (29.09 inHg) | Mozambique, Madagascar | Unknown | 19 | [26] |
| Belal | 11 January – Present | Tropical cyclone | 150 km/h (90 mph) | 964 hPa (28.47 inHg) | Mauritius, Réunion | None | 1 | [41] |
| Season aggregates | ||||||||
| 2 systems | 30 December– Season Ongoing | 150 km/h (90 mph) | 964 hPa (28.47 inHg) | None | 20 | |||
See also
- Weather of 2023 and 2024
- List of Southern Hemisphere cyclone seasons
- Tropical cyclones in 2023 and 2024
- Atlantic hurricane seasons: 2023, 2024
- Pacific hurricane seasons: 2023, 2024
- Pacific typhoon seasons: 2023, 2024
- North Indian Ocean cyclone seasons: 2023, 2024
- 2023–24 Australian region cyclone season
- 2023–24 South Pacific cyclone season
References
- ^ a b "Prévision saisonnière d'activité cyclonique dans le Sud-Ouest de l'océan Indien: Saison 2023-2024" [Seasonal forecast of hurricane activity in the South West Indian Ocean Season 2023-2024]. Météo-France. 26 October 2023. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ a b "Seasonal Outlook for Summer 2023–24". Mauritius Meteorological Services. 30 October 2023. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ a b c Bulletin Cyclonique Special du 01 Janvier 2024 a 20 heures locales (Report) (in French). Météo Madagascar. 1 January 2024. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ a b Zone of Disturbed Weather 02 Warning Number (2/2/20232024) (PDF) (Report). Météo-France. 11 January 2024. Archived (PDF) from the original on 12 January 2024. Retrieved 12 January 2024.
- ^ Bulletin for Cyclonic Activity and Significant Tropical Weather in the Southwest Indian Ocean (PDF) (Report). Météo-France. 24 December 2023. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Bulletin for Cyclonic Activity and Significant Tropical Weather in the Southwest Indian Ocean (PDF) (Report). Météo-France. 29 December 2023. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Tropical Disturbance 01 Warning Number (1/1/20232024) (PDF) (Report). Météo-France. 30 December 2023. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Significant Tropical Weather Advisory for the Indian Ocean, 12Z 30 December 2023 Reissued (Report). United States Joint Typhoon Warning Center. 30 December 2023. Archived from the original on 30 December 2023. Retrieved 1 January 2024.
- ^ Tropical Depression 01 Warning Number (6/1/20232024) (PDF) (Report). Météo-France. 31 December 2023. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Moderate Tropical Storm 1 (Alvaro) Warning Number (7/1/20232024) (PDF) (Report). Météo-France. 31 December 2023. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Tropical Cyclone 04S (Alvaro) Warning No. 1 (Report). United States Joint Typhoon Warning Center. 31 December 2023. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Severe Tropical Storm 01 (Alvaro) Warning Number (10/1/20232024) (PDF) (Report). Météo-France. 1 January 2024. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Prognostic Reasoning for Tropical Cyclone 04S (Alvaro) Warning No. 3 (Report). United States Joint Typhoon Warning Center. 1 January 2024. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ a b Severe Tropical Storm 01 (Alvaro) Warning Number (11/1/20232024) (PDF) (Report). Météo-France. 1 January 2024. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Tropical Cyclone 04S (Alvaro) Warning No. 3 (Report). United States Joint Typhoon Warning Center. 1 January 2024. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Severe Tropical Storm 01 (Alvaro) Warning Number (12/1/20232024) (PDF) (Report). Météo France. 1 January 2024. Archived (PDF) from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ Prognostic Reasoning for Tropical Cyclone 04S (Alvaro) Warning No. 4 (Report). United States Joint Typhoon Warning Center. 2 January 2024. Archived from the original on 2 January 2024. Retrieved 2 January 2024.
- ^ Overland Depression 01 (Alvaro) Warning Number (15/1/20232024) (PDF) (Report). Météo-France. 2 January 2024. Archived (PDF) from the original on 2 January 2024. Retrieved 2 January 2024.
- ^ Moderate Tropical Storm 01 (Alvaro) Warning Number (17/1/20232024) (PDF) (Report). Météo-France. 3 January 2024. Archived (PDF) from the original on 3 January 2024. Retrieved 3 January 2024.
- ^ Prognostic Reasoning for Tropical Cyclone 04S (Alvaro) Warning No. 7 (Report). United States Joint Typhoon Warning Center. 3 January 2024. Archived from the original on 3 January 2024. Retrieved 3 January 2024.
- ^ Post-Tropical Depression 01 (Alvaro) Warning Number (20/1/20232024) (PDF) (Report). Météo-France. 3 January 2024. Retrieved 3 January 2024.
- ^ Post-Tropical Depression 01 (Alvaro) Warning Number (23/1/20232024) (PDF) (Report). Météo-France. 4 January 2024. Archived (PDF) from the original on 5 January 2024. Retrieved 5 January 2024.
- ^ a b "Madgascar: Tropical Storm Alvaro formed in the Mozambique Channel, Dec. 31". Crisis24. 31 December 2023. Archived from the original on 1 January 2024. Retrieved 1 January 2024.
- ^ "Le cyclone Alvaro quitte Morombe, des quartiers se retrouvent sous les eaux" [Cyclone Alvaro leaves Morombe, neighborhoods find themselves under water]. linfo.re. 2 January 2024. Retrieved 2 January 2024.
- ^ Marek, Francine (2 January 2024). "Le Cyclone Alvaro est arrivé sur Madagascar" [Cyclone Alvaro arrived in Madagascar]. afrik.com. Retrieved 2 January 2024.
- ^ a b c d United States Embassy Antananarivo (10 January 2024). "U.S. Provides Assistance in Madagascar to Victims of Storm Alvaro". United States Embassy in Madagascar. Retrieved 10 January 2024.
- ^ "Madagascar - Tropical Cyclone ALVARO (GDACS, BNGRC, Meteo Madagascar) (ECHO Daily Flash of 5 January 2024)". European Commission's Directorate-General for European Civil Protection and Humanitarian Aid Operations. 5 January 2024. Retrieved 5 January 2024 – via reliefweb.int.
- ^ Rakotobe, Narinda (5 January 2024). "Madagascar: Tempête Alvaro - Un bilan de 10 morts et 25 837 sinistrés" [Madagascar: Storm Alvaro - A toll of 10 dead and 25,837 victims]. Midi Madagasikara. AllAfrica. Retrieved 5 January 2024.
- ^ Zone of Disturbed Weather 02 Warning Number (3/2/20232024) (PDF) (Report). Météo-France. 11 January 2024. Archived (PDF) from the original on 12 January 2024. Retrieved 12 January 2024.
- ^ Tropical Cyclone Formation Alert (Invest 97S) (Report). United States Joint Typhoon Warning Center. 12 January 2024. Archived from the original on 12 January 2024. Retrieved 12 January 2024.
- ^ Tropical Depression 02 Warning Number (6/2/20232024) (PDF) (Report). Météo-France. 12 January 2024. Archived (PDF) from the original on 12 January 2024. Retrieved 12 January 2024.
- ^ Tropical Cyclone 05S (Five) Warning No. 1 (Report). United States Joint Typhoon Warning Center. 12 January 2024. Archived from the original on 12 January 2024. Retrieved 12 January 2024.
- ^ Current Storm/Cyclone 13 January 2024 04 AM (Report). Mauritius Meteorological Services. 13 January 2024. Archived from the original on 13 January 2024. Retrieved 13 January 2024.
- ^ Severe Tropical Storm 02 (Belal) Warning Number (10/2/20232024) (PDF) (Report). Météo-France. 13 January 2024. Archived (PDF) from the original on 13 January 2024. Retrieved 13 January 2024.
- ^ Tropical Cyclone 02 (Belal) Warning Number (12/2/20232024) (PDF) (Report). Météo-France. 14 January 2024. Archived (PDF) from the original on 14 January 2024. Retrieved 14 January 2024.
- ^ "Dépression tropicale n°02 : Pre-alerte jaune cyclonique à La Réunion" (in French). Météo-France La Réunion. 12 January 2024. Archived from the original on 12 January 2024. Retrieved 12 January 2024.
- ^ "Belal Alerte orange cyclonique : « Je me prépare »" (in French). Préfét de La Réunion. 13 January 2024. Archived from the original on 13 January 2024. Retrieved 13 January 2024.
- ^ "Belal : Maurice passe en alerte cyclonique de classe 1" (in French). Le Mauricien. 13 January 2024. Archived from the original on 13 January 2024. Retrieved 13 January 2024.
- ^ "France raises cyclone alert to red as Belal approaches its Reunion island in Indian Ocean". www.aa.com.tr. Retrieved 2024-01-14.
- ^ RA I Tropical Cyclone Committee (2023). Tropical Cyclone Operational Plan for the South-West Indian Ocean (PDF) (Report). World Meteorological Organization.
- ^ "One dead as storm hits French Indian Ocean island". Yahoo News. 2024-01-15. Retrieved 2024-01-15.