At 4:00 a.m. on August 22, Typhoon No. 4 was centered over the waters off Quang Ninh and Hai Phong, with maximum sustained winds of Force 8 (62–74 km/h) and gusts reaching Force 10. The storm was moving slowly, bringing strong winds, high waves, and heavy rainfall, with some locations in Quang Ninh and Hai Phong expected to receive more than 600 mm of rain. According to the National Center for Hydro-Meteorological Forecasting, Bach Long Vi Island District in Hai Phong recorded Force 8 winds with gusts up to Force 9, while Co To Island District in Quang Ninh experienced Force 6 winds with gusts up to Force 9. At 4:00 a.m., the storm’s center was located at approximately 21.4°N and 108.4°E, over the waters between Quang Ninh and Hai Phong, about 150 km north-northeast of Bach Long Vi Island. The typhoon was moving northward at around 5 km/h.
In the Gulf of Tonkin, including the island districts of Bach Long Vi, Van Don, Co To, Cat Hai, and Hon Dau Island, winds of Force 6–7 are expected, increasing to Force 8 near the storm center, with gusts up to Force 11. Wave heights are forecast to reach 2–4 meters, creating very rough sea conditions. These hazardous conditions could capsize or damage fishing boats, cargo vessels, tourist boats, and other marine craft. Aquaculture cages, anchorage areas, and coastal infrastructure are also at risk of damage, while fishing, maritime transport, and tourism activities may face significant disruptions.
Along the coastal areas of Quang Ninh Province and Hai Phong City, winds of Force 6–7 with gusts of Force 8–9 are forecast. Strong winds may damage roofs, temporary structures, trees, and billboards, while disrupting power supply, telecommunications, and transportation networks. From August 22 to the night of August 24, heavy to very heavy rainfall is expected across northeastern Viet Nam, southern Phu Tho Province, and Thanh Hoa Province, with widespread totals of 100–200 mm and isolated amounts exceeding 400 mm. Rainfall in Quang Ninh and Hai Phong is forecast to reach 250–350 mm, with some areas receiving more than 600 mm, while Lang Son and Bac Ninh may receive 200–300 mm, locally exceeding 500 mm. Rainfall is likely to continue beyond August 24.
The heavy rain may cause urban flooding, inundation in industrial zones and low-lying areas, rising water levels in rivers and streams, flash floods, and landslides in mountainous regions. Under the influence of the typhoon’s circulation, thunderstorms, whirlwinds, and strong wind gusts may also occur. Authorities have urged residents to closely monitor weather updates and take necessary precautions to protect lives and property.
