Explaining the cause of repeated lightning strikes in Hanoi

On September 30, Hanoi experienced heavy rain that lasted from morning, accompanied by continuous lightning strikes, attracting the attention of the capital's residents.

Thunderstorms with thunder and lightning hit many areas in Hanoi . Photo: Pham Tuan Anh/VNA

According to Dr. Truong Ba Kien, Deputy Director of the Center for Hydrometeorological Research, Institute of Hydrometeorology and Climate Change, Ministry of Agriculture and Environment , the main cause is the formation of a strong wind convergence zone from low to high over Hanoi and surrounding areas. This convergence zone is created by East and Southeast winds carrying moisture from the sea and the Gulf of Tonkin, combined with South and Southwest winds from the South. Meanwhile, the atmosphere is in a humid, highly unstable state due to the influence of weakened circulation from storm No. 10. The convergence of these conditions causes thunderstorms to continuously develop, causing prolonged heavy rain and frequent thunder and lightning.

Dr. Truong Ba Kien added that repeated lightning strikes often occur during severe thunderstorms when thunderclouds are strongly electrically polarized, creating a large potential field between the cloud and the ground. The continuous discharge process can cause lightning to appear repeatedly at the same location or in neighboring areas. The discharge of clouds and the discharge of clouds to the ground also creates lightning. In addition, the interaction between hot and humid air masses and cold air, along with the rapid formation of thunderclouds, further increases the intensity of thunderstorms.

Source: https://baotintuc.vn/van-de-quan-tam/ly-giai-nguyen-nhan-set-danh-lien-hoi-o-ha-noi-20250930192321468.htm