South China Sea: Typhoon Koinu tracking westward southeast of Hong Kong evening Oct. 7 /update 7

Event

Typhoon Koinu is tracking westwards across the South China Sea evening Oct. 7, following landfall over far southern Taiwan early Oct. 5. As of 17:00 CST, the system's center of circulation is approximately 169 km (105 miles) southeast of Hong Kong.

Forecast models indicate that the storm will weaken into a tropical storm as it tracks westward across the South China Sea just off the coast of Guangdong Province, China, through Oct. 9. Koinu is then forecast to weaken and make landfall over Hainan Province, China, early Oct. 10 before weakening further into a tropical depression as it exits into the South China Sea early Oct. 11. The system will likely track southwestwards and make another landfall over Ha Tinh Province, Vietnam late Oct. 11 before dissipating over the far southwestern part of the province afternoon Oct. 12. Some uncertainty remains in the track and intensity forecast, and significant changes could occur in the coming days.

The China Meteorological Administration has issued a yellow typhoon warning (second lowest level on a four-tier scale); heavy rainfall of 5-6 cm (2-2.5 inches) is forecast in eastern Zhejiang, southeastern Fujian, and eastern Guangdong provinces. The city of Guangzhou canceled some flights and trains, while Fujian and Guangdong provinces suspended hundreds of ferries since Oct. 6. Guangdong Province has also suspended dozens of high-speed trains. Pazhou Hong Kong and Macao ports suspended ferries from Oct. 5.

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 additional localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also likely to persist. 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)
Hong Kong Observatory
China Meteorological Administration
Vietnam National Centre for Hydro-Meteorological Forecasting