Why Typhoon Bualoi is moving twice as fast as normal storms

Bualoi slammed into the central Philippines on Friday at 35–40 kph, almost double the typical pace of 15–20 kph. It entered the East Sea, known internationally as the South China Sea, three hours earlier than forecast and is now moving west-northwest toward Vietnam at 30–35 kph. In storm history, only a handful of typhoons: Dot in 1985, Linda in 1997 and Doksuri in 2017, have moved this quickly.

Bualoi is being driven by an exceptionally strong subtropical high that is acting like a conveyor belt, explained Truong Ba Kien, Deputy Director of the Center for Meteorological and Climate Research at Vietnam's Institute of Hydrometeorology and Climate Change. At the same time, a developing monsoon trough is connecting directly to the storm, keeping its track stable and fast, he added.

The environment around Bualoi is also unusually favorable. The atmosphere is clear, with little turbulence or disruptive wind shear. The sea surface is warm and rich in energy, helping the storm stay compact and powerful. This allows Bualoi to both accelerate and maintain strong intensity as it moves, Kien said.

Nguyen Minh Truong, Deputy Dean of Meteorology, Hydrology and Oceanography at Hanoi University of Science, added that three main factors are driving the storm's speed: a strong, uninterrupted steering flow in the mid-troposphere, asymmetrical atmospheric processes within the storm's core, and widespread high sea surface temperatures stretching from the western Pacific to the South China Sea.

Experts also warn that the storm’s west-northwest track is being reinforced by the Coriolis effect, which causes moving air and water in the northern hemisphere to bend to the right. The subtropical high expanding toward Vietnam is nudging Bualoi further north, raising the likelihood of landfall in north-central provinces such as Thanh Hoa or Nghe An.

What makes Bualoi especially dangerous, scientists say, is the combination of speed and intensification. Forecast models show more than a 50% chance that the storm will strengthen by two to three levels within 24 hours, potentially reaching level 13, with wind speed up to 149 kph, or higher while still at sea. Because it is moving so fast, strong winds will penetrate deeper inland than usual. If landfall coincides with high tide at night, the risk of storm surge will be extreme, Kien warned.

Heavy rain is also expected to lash northern and north-central Vietnam, raising the threat of flash floods, landslides in mountain areas, and severe flooding in cities and lowlands. Even after moving into Laos, Bualoi’s circulation could bring dangerous rainfall to western Thanh Hoa, Nghe An and along the Vietnam–Laos border, particularly around hydropower dams and reservoirs.

Authorities are calling for all vessels to urgently return to shore and banning trips to sea. Evacuation plans are being prepared for coastal, low-lying, and landslide-prone areas, while infrastructures such as dikes, homes, schools and hospitals are being reinforced. Residents are urged to secure property, stockpile food and clean water, and follow only official forecasts and warnings.