Indian Ocean: Tropical Cyclone Batsirai tracking southwestwards in the Indian Ocean early Feb. 1 /update 3

Event

Tropical Cyclone Batsirai is tracking southwestwards in the Indian Ocean early Feb. 1. As of 04:00 MUT, the storm's center of circulation was approximately 669 km (416 miles) northeast of Port Louis, Mauritius. Forecast models indicate the system will maintain its strength as it passes north of Mauritius Feb. 2 and Reunion Feb. 3. Although the center of the storm will pass some 150-250 km (93-155 miles) north of the islands, they will likely be impacted by the outer winds of the storm system as it passes. After passing north of the islands, the storm is forecast to strengthen into an intense tropical cyclone as it tracks in a more westerly direction towards the eastern coast of Madagascar Feb. 4-5, before making landfall over central Madagascar's east coast late Feb. 5. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

As of early Feb. 1, the Mauritius Meteorological Services has issued a Class 2 cyclone warning for the main island of Mauritius. The public is advised to take preliminary precautions. A deterioration in weather conditions is expected from late Feb. 1. Frequent showers, winds of around 45 kph (28 mph) with gusts of up to 100 kph (62 mph), and wave heights of around 5 meters (16 feet) are forecast.

Meteo France La Reunion has issued a yellow level pre-alert (the lowest level on a four-tier scale) across the territory due to the approach of the storm system. Strong and frequent rainfall, wind gusts of 100-150 kph (62-93 mph), and waves exceeding 5 meters (16 feet) are forecast late Feb. 1-4.

The Madagascar General Directorate of Meteorology has warned that the cyclone is likely to make landfall on the east coast between Toamasina and Manakara late Feb. 5, with the exact path of the storm expected to become clearer in the coming days. Green pre-warning alerts have been issued for the following districts: Antalaha, Analanjirofo, Toamasina I-II, Vonibany (Brickavill), Vatomandry, Mahanoro, Antanambao, Manampotsy, Nosy Varika, Mananjary, Manakara, Vohipeno, Farafangana, Vangaindrano, and Taolagnaro. Strong winds are expected to be felt from late Feb. 1 on the east coast and seafarers are advised not to venture out to sea.

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)