South China Sea: Tropical Depression 13W tracking north-northwestward towards central Vietnam as of Sept. 25

Event

Tropical Depression 13 W has formed in the South China Sea off the east coast of central Vietnam and is tracking north-northwestward toward the Vietnam coast Sept. 25. As of 13:00 ICT, the system's center of circulation was approximately 128 km (80 miles) east of Da Nang.

Forecast models indicate that the storm will strengthen slightly but remain a depression as it tracks northwestward and then west-northwestward before making landfall over Quang Tri Province early Sept. 26. The system is expected to weaken over land as it tracks generally westward across central Vietnam and central Laos Sept. 26, before dissipating over northeastern Thailand late Sept. 26-early Sept. 27. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

Vietnam's National Center for Hydrometeorological Forecasting (NCHMF) has issued an emergency warning for the storm system, advising that moderate to heavy rainfall is already occurring across parts of central Vietnam and further heavy rainfall, strong winds, and rough seas are forecast in affected areas over the coming hours and days. Rainfall totals of 10-20 cm (4-8 inches) are likely across central regions through Sept. 27, with higher totals possible in parts of Quang Tri and Thua Thien Hue provinces.

Authorities in Da Nang advised vessels to return to shore Sept. 24 due to hazardous sea conditions and beach activities have been banned in Quang Nam from Sept. 25. Flooded roads and associated traffic conditions have been reported in Da Nang, Thua Thien Hue, and Quang Nam as of Sept. 25.

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 (JTWC)
Vietnam National Center for Hydrometeorological Forecasting (NCHMF)