Tropical Storm Bualoi, officially the 10th storm of the year, is heading for landfall with dangerous characteristics that make it particularly difficult to predict and prepare for. Forecasts show the storm will strike between northern Quang Tri and Ha Tinh from late September 28 to early September 29. Due to its fast movement and expansive circulation, the storm may trigger extreme weather conditions across multiple regions.

Unusual features increase storm risk

On the evening of September 27, the National Center for Hydro-Meteorological Forecasting (NCHMF) released an update on Bualoi’s latest developments.

Dr. Hoang Phuc Lam, Deputy Director of the Center, reported that the storm had strengthened to Category 12, with gusts reaching Category 15, and is moving at an extraordinary speed not seen in years.

“It’s rare to see a storm move this fast,” said Lam. Bualoi is currently moving at speeds between 30–35 km/h, at times reaching 40 km/h - twice the average speed of typical storms, which move at only 10–20 km/h, or even as low as 5–10 km/h.

Lam explained that slower-moving storms have more time to accumulate energy and are more likely to change course. But Bualoi’s speed makes any directional shift unlikely. Initial forecasts suggested it might veer north toward Quang Ninh or Hai Phong, but current projections confirm a high probability of landfall in northern Quang Tri or Ha Tinh.

The storm's second dangerous feature is its wide circulation. As early as September 27, areas from Quang Tri to Hue and Da Nang were already experiencing heavy rainfall due to the outer cloud bands. These bands cause intermittent showers, but once the storm’s main body reaches an area, the rain becomes continuous, varying in intensity but without breaks, according to Lam.

He warned that these regions could see continued heavy rainfall overnight on September 27, raising the risk of urban flooding.

Storm could maintain strength upon landfall

Due to the storm’s rapid movement and its trajectory along the coast from south to north, the area of impact will continue to widen.

By the evening of September 27, strong winds had begun affecting the sea from Thanh Hoa to Quang Ngai, including islands like Hon Ngu, Con Co, and Ly Son. Wind speeds increased to Category 6–7 with gusts at Category 8–9. Waves reached 3–5 meters, and the sea became increasingly rough.

From early morning on September 28, wind speeds are forecast to reach Category 8–9, and in areas near the storm's center, up to Category 10–13 with gusts at Category 16. Waves will reach 5–7 meters, posing serious risks to large vessels.

The Gulf of Tonkin, including Bach Long Vi, Van Don, Co To, Cat Hai, and Hon Dau islands, will also see increasing winds from Category 6–7 to Category 8–9, with gusts reaching Category 11.

Lam emphasized that the first areas to feel the storm’s direct impact on land will be in northern Quang Tri. From the afternoon of September 28, wind speeds in this region are expected to rise to Category 6–7, intensifying to Category 8–9 by nightfall. The peak intensity will occur overnight into the early hours of September 29.

The strongest winds - reaching Category 10–12 and gusting to Category 14 - will occur in Thanh Hoa to northern Quang Tri, potentially toppling trees, tearing off roofs, and bringing down power lines.

Coastal areas from Quang Ninh to Ninh Binh and from southern Quang Tri to Hue will also see increasing winds at Category 6–7, with gusts up to Category 9.

Lam declared a natural disaster risk level of 4 (very high) for coastal land areas from Nghe An to northern Quang Tri.

Up to 600mm of rain in some areas

From now until September 30, widespread heavy rain is expected in northern Vietnam and areas from Thanh Hoa to Quang Ngai, with rainfall ranging from 100–300 mm. Some locations could exceed 450 mm. In the Red River Delta, southern Phu Tho, and from Thanh Hoa to northern Quang Tri, totals could reach 200–400 mm, and isolated areas may see over 600 mm.

Lam reiterated that Bualoi’s rapid approach means rain is already falling ahead of the storm’s center. The system is unlikely to weaken before landfall, and significant rainfall is expected as early as September 27, gradually shifting northward.

By the afternoon of September 28, hurricane-force winds are expected to intensify across areas from Quang Tri to Thanh Hoa.

Lam urged local authorities in the storm’s projected path to step up communication efforts and implement emergency response plans immediately. He also stressed the importance of monitoring storm forecasts and advisories closely.

For residents, staying informed via official channels and following government-issued evacuation and safety orders is critical.

Widespread flooding and landslide risks

Hoang Van Dai, Deputy Director of the NCHMF, added that from September 28 to 30, major flooding is expected on rivers across the north and from Thanh Hoa to Quang Tri.

In Thanh Hoa, rivers like the Buoi, Ma, and Chu may reach alarm levels 2–3, or even exceed level 3. Lower sections of these rivers may reach levels 1–2.

In Nghe An, rivers such as the Ca may also rise to levels 2–3, while the lower Ca River is expected to exceed level 1.

In Ha Tinh, rivers like the Ngan Sau and Ngan Pho could reach levels 2–3, and the La River is forecast to exceed level 1.

In Quang Tri, the Gianh River may reach levels 1–2, and the Kien Giang River may rise to levels 2–3.

There is a high risk of widespread flooding across the Red River Delta and from Thanh Hoa to northern Quang Tri, with severe inundation expected particularly from Thanh Hoa to Ha Tinh.

There is also an extremely high risk of flash floods and landslides in provinces such as Son La, Phu Tho, Lao Cai, and from Thanh Hoa to Quang Tri.

Bao Anh