Madagascar: Tropical Storm Gamane tracking southwestward over eastern Diane Region as of March 27 /update 3

Severe Tropical Storm Gamane is tracking southwestward over eastern Diane Region March 27, having made landfall as a tropical cyclone in Vohemar District, Sava Region, early March 27. As of 15:00 EAT, the storm's center of circulation was approximately 646 km (401 miles) north-northeast of Antananarivo, Madagascar.

Forecast models indicate the system will weaken into a moderate tropical storm as it tracks south-southwestward into southern Diane Region through early March 28, before weakening further into a tropical depression as it tracks south-southeastward and then southeastward over northeastern Sofia Region and northern Analanjirofo Region March 28. Gamane is expected to move over southern Sava Region early March 29 before moving back into the Indian Ocean. The system will strengthen back into a moderate tropical storm as it tracks southeastward away from Madagascar March 29-31 before making a close approach to Mauritius late March 31, passing just southeast of the main island. After passing Mauritius, Gamane is expected to weaken and transition into a post-tropical cyclone as it tracks southeastward away from the Mascarene Islands. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

As of March 27, Meteo Madagascar has issued red cyclone alerts (the highest level on a three-tier scale) for the Diane and Sava regions and yellow cyclone alerts for the Analanjirofo Region. Red heavy rainfall warnings have been issued for Amparafaravola and Andilamena districts in Alaotra-Mangoro Region, Belalanana, Befandriana-Nord, and Mandritsara districts in Sofia Region, and Toamasina and Vohibinany districts in Atsinanana Region. Yellow heavy rainfall warnings have been issued for the Analalava and Antsohihy districts in the Sofia Region, and green heavy rainfall warnings are in place across the rest of Atsinanana Region and Ambatondrazaka and Anosibe An'ala 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 March 27 and the heavy rainfall is expected to persist through at least March 28. Reports indicate flooding is affecting parts of Sava Region as of March 27, including the towns of Antalaha, Sambava, and Vohemar. Several homes in the region have been inundated by floodwaters, and a number of roads have been made impassable. Damage assessments may take some time due to the ongoing severe weather weather associated with Gamane and it may take some time before the full extent of the storm system's impacts can be confirmed.

The Mauritius Meteorological Service has issued a severe weather warning advising that severe weather is possible over Mauritius March 30-April 1, depending on the evolution of the storm system.

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.