2021–22 South-West Indian Ocean cyclone season

The 2021–22 South-West Indian Ocean cyclone season had the latest start on record. Despite the late start, it was an above-average season that produced 12 named storms, with five becoming tropical cyclones. The season began on 15 November 2021, and ended on 30 April 2022, with the exception for Mauritius and the Seychelles, for which it ended on 15 May 2022. 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 that form at any time between July 1st, 2021 and June 30th, 2022 will count towards the season total. 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.

__TOC__

Seasonal summary

The season's first storm, Moderate Tropical Storm Ana, formed as a zone of disturbed weather on 20 January 2022, marking the latest first system in a Southwest Indian Ocean cyclone season ever. The second, and strongest storm of the season, Cyclone Batsirai, formed on 24 January, and became a long-lived and powerful storm. It cruised west, and eventually made landfall in Madagascar as a Category 3-equivalent storm. While Batsirai impacted Madagascar, Moderate Tropical Storm Cliff quickly formed but stayed out to sea. Continuing the active period of development, Tropical Storm Dumako formed, struggling to intensify and making landfall in Madagascar later.

Yet another storm, Cyclone Emnati, would strike extreme southern Madagascar as a Category 1-equivalent after peaking as a Category 4-equivalent beforehand. The third Intense Tropical Cyclone, Cyclone Vernon, passed into the basin as a Category 4-equivalent after very rapidly intensifying in the neighboring Australian region. The fourth Intense Tropical Cyclone, Gombe, formed off the coast of Madagascar on 5 March. Initially, the storm struggled to intensify beyond tropical storm status. After hitting Madagascar, Gombe emerged into the Mozambique Channel and rapidly intensified to a Category 3-equivalent cyclone. It then struck Mozambique, bringing heavy rainfall to the same area which Ana had hit a few weeks ago. After Gombe, Halima formed in the northeast of the basin on 21 March. It gradually intensified to an Intense Tropical Cyclone on 25 March, before dissipating later on 1 April. After, Subtropical Depression Issa formed just off the eastern coast of South Africa, an extremely rare phenomenon. It proved itself to be damaging and very deadly, killing hundreds due to catastrophic flooding. Finally, Jasmine formed near Comoros on 21 April before the landfall in Nampula and Zambezia province off the coast of Mozambique and rapidly intensified as Severe Tropical Storm. The storm made landfall in Toliara before it rapidly weakening to an overland depression, and dissipated on 27 April. In early May, Karim formed. Karim did not affect land and entered the Australian region on 7 May.

Systems Severe Tropical Storm Ana

On 20 January, the Joint Typhoon Warning Center began monitoring an area of convection approximately from Mauritius, and gave a low chance for potential tropical cyclogenesis within the next 24 hours. Alt URL Early the next day, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) for the system, as it consolidated a well-defined low-level circulation center (LLCC). Alt URL Later at 12:00 UTC, the MFR declared the tropical low pressure system as a zone of disturbed weather, becoming the first system of the season. Twelve hours later, the MFR upgraded it to a tropical disturbance, before further upgrading it to a tropical depression by 06:00 UTC on 22 January. Between 08:00 UTC and 09:00 UTC, the system's center crossed between Toamasina and Île Sainte-Marie as a tropical depression, with the MFR re-classifying the system as an overland depression. Following landfall, the system weakened slightly, though its structure remained intact. By the next day, the MFR re-classified it again as a tropical disturbance after entering the Mozambique Channel. Six hours later, it re-intensified into a tropical depression, as it gradually regained its structure. At 15:00 UTC that same day, the JTWC upgraded the system to a tropical cyclone and designated it 07S. Alt URL The system later intensified to a moderate tropical storm, with the MFR naming it Ana. It then made landfall in Mozambique, and rapidly weakened, primarily due to friction in land mass.

Despite being a weak system, Ana caused devastating floods in Madagascar, Malawi, and Mozambique, killing 115 people in total. Before becoming a moderate tropical storm, Ana made landfall as a tropical depression in Madagascar, causing heavy rainfall which led to deadly landslides and floods; it caused 58 fatalities in the country. An estimated 55,000 people had become homeless and 130,000 were forced to flee to temporary habitation centres. In Mozambique, at least 20 people had died and 10,000 homes had been destroyed. An additional 20,000 were affected by the cyclone. In Malawi, 200,000 people had been displaced and 37 fatalities had been reported, with additional 22 being missing. Catastrophic flooding caused severe damages to infrastructure and powerlines, which led to severe power outages in the affected areas. The Kapichira hydroelectric dam was badly damaged due to the flash floods. Because of this, the government of Malawi declared a state of natural disaster.

Intense Tropical Cyclone Batsirai

On 23 January, the JTWC noted an area of convection over the eastern part of the basin, located approximately from the Cocos Islands, and gave a low chance for potential tropical cyclogenesis. Alt URL However, by the next day, the agency issued a TCFA. Alt URL At 06:00 UTC on 26 January, the MFR upgraded the system to a tropical disturbance, before the system intensified into a tropical depression on the next day. The JTWC upgraded the system to a tropical cyclone at 03:00 UTC on 27 January. Alt URL Three hours later, the MFR upgraded it to a moderate tropical storm, naming it Batsirai. Between 06:00 UTC and 12:00 UTC, Batsirai underwent rapid deepening and intensified from a moderate tropical storm to an intense tropical cyclone within three hours. Two hours later, the JTWC upgraded it to a Category 2 tropical cyclone. Alt URL The system started to rapidly weaken after its eye quickly collapsed and the cloud tops had warmed, so the MFR downgraded it to a tropical cyclone. At midnight on 28 January, it was further downgraded to a moderate tropical storm. The JTWC subsequently followed suit and downgraded it to a tropical storm. Alt URL

Batsirai resumed its intensification after re-intensifying to a severe tropical storm status on the next day. By January 30, the JTWC upgraded it to a Category 2 tropical cyclone once again. Alt URL The MFR further upgraded it to a tropical cyclone status at 12:00 UTC that same day. Three hours later, the JTWC upgraded it to a Category 3 tropical cyclone. Alt URL However, it was short-lived, and it weakened to a Category 1 system on 1 February. Alt URL Alt URL The system then restrengthened back to Category 2 status. Alt URL The MFR susbsequently upgraded Batsirai to an intense tropical cyclone. By the next day, it went through another round of rapid intensification, strengthening from a Category 2 to a Category 4 tropical cyclone, according to the JTWC. Alt URL After reaching its peak at 12:00 UTC, satellite imagery depicted the formation of another eyewall, indicating the beginning of an eyewall replacement cycle. Alt URL It weakened to a Category 3 system during this time. After completing the eyewall replacement cycle, the storm again briefly intensified into a Category 4 system, Alt URL before it started to weaken again to a Category 3 system, due to land interaction with Madagascar. Alt URL At 17:30 UTC on 5 February, it made landfall close to the city of Nosy Varika. The MFR declared that Batsirai had degenerated into an overland depression, with the JTWC downgrading it to a tropical storm. Alt URL The system entered into the Mozambique Channel, where it re-intensified to a moderate tropical storm. By 7 February, it weakened into a remnant low before transitioning into a post-tropical cyclone. Despite fluctuating convective activity, high wind shear, and low sea surface temperatures, due to baroclinic forces, the MFR upgraded the system to a moderate tropical storm once more, before issuing their last advisory on the storm by the next day as it again transitioned into a post-tropical cyclone. The system was last noted on 11 February.

Batsirai caused major impacts to Mauritius, Réunion, and Madagascar, caused $190 million in damages, and caused 123 people to die. In Mauritius and Reunion, an estimated 43,500 homes lost power due to the storm. A total of 138 people sought refuge in evacuation centers.ref> Power girds in Madagascar were also knocked out. Agricultural losses in Reunion amounted an estimated €47 million (US$53.1 million).

Moderate Tropical Storm Cliff

On 31 January, the MFR reported the formation of a weak area of low pressure east of Cyclone Batsirai, which the JTWC recognized as Invest 90S at 08:00 UTC of 2 February. Alt URL Two days later at 03:00 UTC, the JTWC issued a TCFA for the invest, Alt URL upgrading it to a tropical cyclone shortly after, noting the defined but obscured LLC. Alt URL At midday, the MFR followed, and declared the same low as a tropical depression. Later in the evening, the MFR upgraded it to a moderate tropical storm and was given the name Cliff. By midnight of 5 February, Cliff weakened as it lost organization, with its convection being displaced south of its LLC. By 06:00 UTC, Cliff further weakened due to an intrusion of dry air and further strengthening of northwesterly wind shear. Six hours later, the MFR issued its last bulletin and declared it as a "filling up" low. On the next day at 21:00 UTC, the JTWC also issued its final warning on Cliff. Alt URL The remnants of Cliff meandered in the open-sea and briefly passed west of the Reunion island on 11 February, dissipating completely on 12 February.

Moderate Tropical Storm Dumako

On 10 February, MFR began monitoring an area of disturbed weather, with the JTWC designating the system as an invest a day later. Alt URL By 12 February, it had been upgraded to a tropical disturbance by MFR, before being upgraded to a tropical depression later that day. The JTWC assessed that the system had developed into a tropical cyclone on 13 February, giving it the designation 12S. Alt URL MFR upgraded the system to a moderate tropical storm later that day, being given the name Dumako by the Mauritius Meteorological Service. By 14 February at 00:00 UTC, MFR estimated Dumako to have peaked in intensity, with maximum 10-minute sustained winds of and a minimum central pressure of . Dumako continued westward, and by the next day, it had made landfall near Sainte-Marie Island. MFR downgraded Dumako to a tropical depression later that day, with the JTWC doing the same at 00:00 UTC on 16 February. Dumako re-emerged over water on the same day, before being assessed to have lost tropical depression status by MFR on 17 February. Dumako dissipated on 18 February as it made landfall over Mozambique close to the city of Quelimane.

In Madagascar, at least 113 houses were damaged, more than 5000 people were affected. Flooding killed at least 14 people in Madagascar and 4,323 people were displaced. Heavy rain was recorded in South Malawi and caused flooding in some areas. The city of Quelimane experienced flooding, with power lines experiencing damage. 160 families were displaced and of crops were destroyed in Malema District. No deaths were reported in Mozambique and Malawi. Losses are estimated at US$5 million.

Intense Tropical Cyclone Emnati