Indian Ocean: Tropical Depression Five forms in the western Indian Ocean Jan. 12

Tropical Depression Five has formed in the western Indian Ocean and is tracking southwestward to the east of Madagascar Jan. 12. As of 16:00 RET, the storm's center of circulation was approximately 759 km (472 miles) north of Port Louis, Mauritius.

Forecast models indicate the system will strengthen into a moderate and then severe tropical storm as it tracks generally southwestward through Jan. 13. The storm, which is set to be named Belal, is expected to strengthen further into a tropical cyclone as it turns to track southward and then southeastward towards Reunion and Mauritius Jan. 14. The system is forecast to reach intense tropical cyclone strength Jan. 15 before passing between Reunion and Mauritius late Jan. 15. Having passed the islands, the system is expected to weaken back into a tropical cyclone as it tracks southwestward away from the Mascarene Islands through Jan. 17. Some uncertainty remains in the track and intensity forecast; significant changes could occur in the coming days.

As of late Jan. 12, Meteo France La Reunion has issued a yellow pre-cyclone warning (the lowest level on a four-tier scale) across eastern, southeastern, and southern parts of the territory. Yellow heavy rain and thunderstorm warnings are also in place for these areas. The Mauritius Meteorological Service has yet to issue any warnings for the cyclone but has stated it expects to issue a class one (out of four) cyclone warning Jan. 13. Strong winds and showers are expected to begin to impact both Reunion and Mauritius Jan. 13 and will intensify over the coming days as the storm approaches. Officials will likely issue new alerts or update/rescind existing advisories as the storm progresses.

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.