Madagascar: Tropical Storm Gamane tracking southwestward over Sofia Region as of late March 28 /update 5

Moderate Tropical Storm Gamane has weakened into a zone of disturbed weather and is tracking southwestward over the Sofia Region late March 28, having made landfall as a tropical cyclone in Vohemar District, Sava Region, early March 27. As of 18:00 EAT, the storm's center of circulation was approximately 533 km (331 miles) north of Antananarivo, Madagascar.

Forecast models indicate the system will continue southeastward over the Sofia Region through March 28, then far northern Analanjirofo Region before exiting into the Indian Ocean the afternoon of March 29. The system will strengthen back into a tropical depression as it tracks southeastward away from Madagascar March 30 and weaken back into a zone of disturbed weather March 31. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

As of early March 28, Meteo Madagascar is maintaining blue post-cyclone alerts for the Diane, Sava, Ambatosoa, and Analanjirofo regions. Red heavy rainfall warnings have been issued for the Diane, Sava, Ambatosoa, and Analanjirofo regions, and Toamasina and Vohibinany districts in the Atsinanana Region. Green heavy rainfall warnings are in place across Analalava, Antsohihy, Bealanana, Mandritsara, Befandriana North, Antanambao Manampotsi, Marolambo, Mahanoro, and Stone districts in Alaotra-Mangoro Region. Red strong wind and heavy swell warnings are in place for much of Madagascar's eastern, northeastern, and southern coastlines. Maritime operators are advised not to venture out to sea between Antsiranana and Mahanoro, as well as between Analalava and Antsiranana, due to dangerous sea conditions. Severe weather is ongoing across much of northern and northeastern Madagascar as of late March 28 and the heavy rainfall is expected to persist through at least March 29.

Reports indicate flooding is affecting parts of the Sava Region, including the towns of Antalaha, Sambava, and Vohemar, killing 11 people and displacing 2,560 people. More than 600 homes in the region have been inundated by floodwaters. Several roads across northern Madagascar are impassable, including parts of national roads 5 and 6. Damage assessments may take some time due to the ongoing severe weather associated with Gamane.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. Localized evacuations, flash flooding, and landslides are possible. The inclement weather could trigger localized business, transport, and utility disruptions, rendering 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. Raw sewage and other hazardous materials mixed with floodwaters pose a serious health threat.