Mozambique Channel: Severe Tropical Storm Cheneso remains nearly stationary in Mozambique Channel Jan. 25 /update 5

Event

Severe Tropical Storm Cheneso remains nearly stationary in the Mozambique Channel off the western coast of Madagascar Jan. 25. As of 15:00 EAT, the storm's center of circulation was approximately 380 km (236 miles) northeast of Europa Island.

Forecast models indicate that the system will strengthen into a tropical cyclone as it continues to remain nearly stationary Jan. 25 before starting to track generally southwestward Jan. 26. The system is forecast to stay well over 100 km (62 miles) off the western and southwestern coasts of Madagascar as it tracks southwestward and then southward in the Mozambique Channel Jan. 26-28, briefly reaching intense tropical cyclone strength Jan. 27. The system is then likely to weaken back into a tropical cyclone and then a severe tropical storm as it tracks southward and then southeastward into the southern Indian Ocean Jan. 28-30, curving around southwestern Madagascar before moving away from the country to the southeast. Although it is not forecast to make another landfall, Cheneso is likely to impact the western and southwestern coasts of Madagascar as it passes over the coming days. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

As of Jan. 25, the Madagascar General Directorate of Meteorology has issued yellow cyclone alerts (the middle level on a three-tier scale) for Belon'i Tsiribihina, Manja, and Morondava districts in Menabe Region and Morombe and Toliara I-II districts in Atsimo-Andrefana Region. Wind gusts of 50-80 kph (31-50 mph) are forecast along the coasts of Atsimo-Andrefana and Menabe regions Jan. 25-26. Additionally, heavy rainfall of 3-6 cm (1.2-2.4 inches) is forecast across Atsimo-Atsinanana, Melaky, and Menabe regions as well as Analalava and Antsohihy districts in Sofia Region through Jan. 26. Authorities have issued yellow heavy rain warnings for these areas. Red strong wind warnings (the highest level on a three-tier scale) have been issued for much of the western, southwestern, and southeastern coastlines, as well as yellow strong wind warnings for parts of the northwestern coastline. Red strong swell warnings have been issued for parts of the western coastline and yellow warnings for parts of the northwestern, southwestern, and southeastern coastlines. A flood watch remains in force for the Betsiboka River basin in Betsiboka Region. Authorities will likely publish new advisories or update/rescind existing alerts throughout the system's progression in the coming days.

The system previously made landfall as a moderate tropical storm over Sava Region in northeastern Madagascar Jan. 19 before largely dissipating as it tracked southwestward over northern and west-central Madagascar Jan. 20-23. Flooding-related disruptions have been reported across many parts of northern and central Madagascar following the passage of the storm system. As of Jan. 25, the National Office for Risk and Disaster Management (BNGRC) has reported eight fatalities associated with the passing of Cheneso; at least 20 other people are missing. The storm has impacted more than 46,000 people across the country and has displaced more than 20,000 people. Over 12,000 homes have been damaged, and more than 500 homes have been destroyed by flooding across the affected areas. Cheneso has also damaged dozens of schools, roads, and other infrastructure. Authorities have preemptively evacuated a number of residents along the Betsiboka and Mahajamba rivers in Betsiboka Region due to the risk of flooding. Areas where the ground is already saturated will be particularly susceptible to flooding during further heavy downpours associated with the storm system.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. Further evacuations, flash flooding, and landslides are possible where weather conditions prove hazardous. The inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Flight disruptions at airports in the region and temporary closures of ports are also possible. Stagnant pools of water during and after flooding may increase the incidence of 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. 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
Madagascar General Directorate of Meteorology