Super Typhoon Rasaga May Strike the South China Sea

Storm after storm, prolonged extreme weather
On September 19, Vietnam’s National Center for Hydro-Meteorological Forecasting (NCHMF) released two advisories: one for Typhoon Mitag and another for the newly formed Rasaga east of the Philippines, which may become Typhoon No. 9. Experts caution that Rasaga could develop into one of the strongest storms of the year.

The impact of Mitag was already felt in southern Vietnam. On September 18, Ho Chi Minh City endured over two hours of heavy rain, flooding major streets and crippling traffic during rush hour. Some areas, such as Ben Cat, recorded more than 120 mm of rainfall, while Binh Chanh and Le Minh Xuan saw nearly 100 mm. Widespread downpours also hit provinces across the Mekong Delta.

By the evening of September 19, Mitag had made landfall in Guangdong, China, with winds of 75–88 km/h before weakening inland. However, its circulation, combined with a tropical convergence zone, continued to trigger heavy rains across Vietnam, especially from Quang Tri down to Lam Dong and the southern provinces.

Rasaga could reach Category 5 intensity
Rasaga formed east of the Philippines on September 18 with winds of 62–74 km/h, gusting to 90 km/h. Though still 1,000 km from Luzon, NCHMF issued early warnings on September 19. The storm is expected to enter the northeast South China Sea by September 23, becoming Typhoon No. 9.

From September 22–23, the storm’s circulation will strengthen winds in the northeast South China Sea to levels 8–9 on the Beaufort scale, with potential gusts far stronger. Projections suggest Rasaga could escalate into a super typhoon, with winds at Category 5 strength — 230–280 km/h — and waves exceeding 10 meters. If it stays on track, northern and central Vietnam could face direct landfall, with widespread torrential rains and destructive winds.

HCMC faces risk of flooding during high tides
Forecasters warn that Rasaga’s heavy rains may coincide with the lunar high tide in late September, compounding flood risks in Ho Chi Minh City and the Mekong Delta. Severe thunderstorms, strong gusts, and lightning are also expected, raising the risk of fallen trees, power outages, and structural damage.

Le Dinh Quyet, Head of Forecasting at the Southern Regional Hydrometeorological Station, noted that while most models predict Rasaga to be extremely powerful, its track skirting southern China could weaken it before reaching Vietnam. However, he urged the public to remain vigilant, as storm paths and intensities often shift unexpectedly.

Five more storms expected by year’s end
From October to December, the South China Sea may see five more tropical storms or depressions, two of which could make landfall in Vietnam, according to NCHMF. Central Vietnam, in particular, will face repeated rounds of heavy rainfall, while cold air masses starting November may complicate weather patterns further.

Mekong River dams release water ahead of storms
In anticipation of severe weather, hydroelectric dams along the Mekong in Thailand and Laos have begun releasing water. Some reservoirs in Laos are already at 90–100% capacity. Sudden discharges, combined with storm rainfall, could trigger flash floods in downstream communities.

The Southern Institute for Water Resources Planning forecasts water levels in the Mekong Delta’s upstream rivers to peak at 3.25 meters in Tan Chau next week — manageable for agricultural infrastructure. Still, low-lying and coastal areas, particularly Ca Mau and flood-prone zones in Hau Giang and Kien Giang, may suffer from inundation during high tides between September 21–23.

👉 Rasaga is being closely watched as potentially one of the most dangerous storms of 2025. Authorities urge communities to prepare emergency plans now and stay updated as forecasts evolve.