Indian Ocean: Tropical Cyclone Batsirai tracking westwards in the Indian Ocean early Feb. 4 /update 6

Event

Intense Tropical Cyclone Batsirai is tracking westwards in the Indian Ocean early Feb. 4. As of 04:00 RET, the storm's center of circulation was approximately 191 km (119 miles) northwest of St. Denis, Reunion. Forecast models indicate the system will maintain its intense tropical cyclone strength as it tracks away from Reunion Feb. 4. The storm is forecast to turn west-southwestwards towards the eastern coast of Madagascar Feb. 4-5 and make landfall over central Madagascar's east coast the evening of Feb. 5. The storm system will weaken rapidly into a moderate tropical storm as it tracks southwestwards over central Madagascar Feb. 5-6 before emerging in the Mozambique Channel early Feb. 7. Batsirai is forecast to strengthen slightly as it tracks southwestwards the southwards in the channel through early Feb. 9. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

Disruptions have been reported in Mauritius and Reunion as of early Feb. 4. In Mauritius, 7,500 people lost power Feb. 2, although utility providers have restored power for 5,900 individuals as of Feb. 3. Authorities established 25 shelters which received 139 people during the passage of the storm. Flights have resumed at Sir Seewoosagur Ramgoolam International Airport (MRU) Feb. 3 after operations were suspended late Feb. 1. A motorcyclist died after hitting a fallen tree in Trou-aux-Biches Feb. 3 and a tree fell on a home on the outskirts of Port Louis Feb. 2.

In Reunion, initial reports indicate 12 people have been injured in storm-related incidents. Power outages were reported nationwide but as of early Feb. 4, most power has since been restored. Almost 50,000 people are also estimated to be without water supply in the western and southern municipalities due to preventative cuts at pumping stations to avoid damages during the passage of the storm. Authorities have set up 143 shelters across the island and schools have been closed until Feb. 7. The main coastal road has been closed as a precaution Feb. 3 due to the threat of coastal flooding. Flights at Roland Garros Airport (RUN) are scheduled to resume from 10:00 Feb. 4 following cancellation late Feb. 2.

Government Advisories
The Mauritius Meteorological Services has lifted all cyclone warnings following the passing of the storm; however, a high wave warning is in place until 16:00 Feb. 4.

Meteo France La Reunion is maintaining a red cyclonic alert (the highest level on a four-tier scale) across the territory through early Feb. 4, with residents advised to shelter at home until the storm has passed. Wind gusts of 100-130 kph (65-81 mph) are forecast over the northwest coast and 120-150 kph (75-93 mph) over mountainous regions. Heavy rainfall is forecast over the mountainous areas and interior of the island.

The Madagascar General Directorate of Meteorology has warned that the cyclone is likely to make landfall on the east coast between Vatomandry and Mananjary 08:00-12:00 EAT Feb. 5. As of late Feb. 3, the following warnings have been issued ahead of the storm's approach:

• Yellow level cyclone threat alerts (the middle tier on a three-tier scale): Atsinanana, Vatovavy, Fitovinany, Atsimo Astinanana, Mangoro, Analamanga, Bongolava, Itsay, Vakinankaratra, Amoron'i Mania, Matsiatra, Ambony, and Ihhorombe regions; and Soanierana Ivongo, St. Marie, Fenerive Is, Vavatenina, Amparafaravola, and Ambatondrazaka districts.

• Green level warning alerts: Anosy and Menabe regions; and Antalaha, Maroantsetra, Mananara Nord, Mandritsara, Andilamena, Tsaratanana, Maevatanana, Antsalova, Beroroha, Sakaraha, Ankazoabo, Morombe, Toliara I-II, Betioky, and Benenitra districts.

Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible.

The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

Joint Typhoon Warning Center
Mauritius Meteorological Services
Madagascar General Directorate of Meteorology (French)
Meteo France Reunion (French)