South China Sea: Typhoon Koinu tracking west-northwestward southeast of Hong Kong early Oct. 8 /update 8

Event

Typhoon Koinu is tracking west-northwestward across the South China Sea early Oct. 8, following landfall over far southern Taiwan early Oct. 5. As of 05:00 CST, the system's center of circulation is approximately 124 km (77 miles) southeast of Hong Kong.

Forecast models indicate that the weather system will weaken into a tropical storm as it turns to track southwestward across the South China Sea just off the coast of Guangdong Province, China, through early Oct. 10. Koinu is forecast to make landfall over far northern Hainan Province 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 early Oct. 12 before dissipating over Khammouane Province in Laos early Oct. 13. 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 10-15 cm (4-8 inches) is forecast in the central coast of Guangdong and near the Pearl River Estuary. 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. Hong Kong and Macao ports suspended ferries from Oct. 5.

The Vietnam National Centre for Hydro-Meteorological Forecasting (NCHMF) has issued a warning for severe weather across central Vietnam Oct. 8. Thunderstorms and heavy rainfall of 2-4 cm (0.8-1.6 inches) are forecast from Nghe An to Quang Binh provinces Oct. 8. The NCHMF has issued a level 1 warning of natural disaster risk due to tornadoes, lightning, and hail in the affected regions.

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