Rare, strong rainstorm hits northern Vietnam, delivering 26 m/s gusts in Quang Ninh

After three days of intense heat, heavy to very heavy downpours affected regions including Quang Ninh, Hanoi, Phu Tho, Lao Cai, Thai Nguyen, Hai Phong, Bac Ninh, Hung Yen, and Ninh Binh, according to the National Center for Hydrometeorological Forecasting.

The storm brought intense thunder, funnel clouds, and powerful squalls.

The strongest gusts reached 26 meters per second (m/s) at Bai Chay in Quang Ninh Province and 20.7 m/s at Bach Long Vi Island in Hai Phong City—wind speeds equivalent to storm-force or tropical depression conditions.

The storm inflicted significant damage in many localities.

In Hanoi, thunderstorms rolled in around 4:00 pm, unleashing fierce winds that knocked over numerous trees and electric poles and crushed several moving vehicles.

In apartment buildings, false ceilings collapsed under the force of the wind, and many motorbike riders on the streets were knocked down by the gusts.

A particularly tragic incident occurred in Quang Ninh at around 2:00 pm, when a thunderstorm with violent gusts capsized a tourist boat carrying 49 people in Ha Long Bay, resulting in 35 deaths and leaving four people missing as of 10:00 am on Sunday.

According to the center, these rainstorms were not driven by the circulation of typhoon Wipha, which has entered the East Vietnam Sea and is forecast to reach the Gulf of Tonkin on Monday.

As of Sunday morning, Wipha remained about 1,000 km east of Quang Ninh and had not directly affected the Gulf of Tonkin.

Instead, the storms were triggered by a tropical convergence zone moving across the northern region, intensified by persistently high temperatures over the past three days. This combination fostered strong upward air currents within an unstable atmosphere, sparking intense thunderstorms.

Meteorologists classified the system as a tropical mesoscale convective system (MCS)—a medium-scale cluster of thunderstorms that often brings very heavy rainfall and hazardous weather, and is relatively rare.

An MCS typically has a diameter ranging from several to hundreds of kilometers, can persist for up to 24 hours, and is more intense and long-lasting than individual thunderstorms.

The most concerning aspect is that such thunderstorms are nearly impossible to forecast well in advance, domestically or internationally, due to their rapid development.

Even with today's high-resolution satellite imagery and weather radar, meteorological agencies can only detect these storms shortly before they hit, typically issuing warnings just 45 minutes to an hour beforehand.

Therefore, this is an extremely dangerous weather phenomenon, especially since it typically occurs in the late afternoon and evening, when many people are traveling on the roads, the center warned.