The recent thunderclaps in Hanoi have been intense and continuous, not startling but lasting for tens of minutes, or even 1 to 2 hours. What could explain this phenomenon? Is it something unusual?
In the past few days, the evening and nighttime thunderstorms in Hanoi have been accompanied by a significant amount of thunder. The thunder is not booming but rather rumbling, continuous, and fairly steady, lasting for an hour or more. Why is this happening?
According to the ABC channel, thunderstorms can produce varying amounts of lightning depending on their development conditions. The more tiny water droplets or hailstones collide within a storm, the more lightning is generated, which naturally leads to louder thunder.
Thunder accompanies very loud lightning. (Illustrative image: Shutterstock).
However, the quantity of lightning is not the sole factor determining the loudness of thunder.
The continuous, rumbling thunder experienced in the recent thunderstorms in Hanoi occurs under specific conditions, including a strong temperature inversion, specifically a layer of warm air trapped between two layers of cooler air.
Typically, temperature decreases as altitude increases. However, sometimes a temperature inversion can occur because the air near the ground cools down faster than the air above it. This creates a temperature inversion that retains sound waves from the storm. These sound waves bounce back and forth between the ground and the aforementioned inverted air layer, traveling far and producing very deep, almost continuous sounds.
Sound waves can also bounce off hills, tall buildings, etc., causing the sound to last even longer.
Temperature inversions often occur in the late afternoon, evening, nighttime, and early morning, therefore the phenomenon of continuous rumbling thunder is also likely to happen during these times. The thunderstorms in Hanoi over the past few days have mostly occurred in the evening and at night, making this phenomenon quite understandable.
In some thunderstorms with a lot of lightning, thunder can rumble continuously for hours. (Illustrative image: Fendy Gan).
Additionally, another factor to consider is the distance from the lightning strike to the listener. We see a flash of lightning but do not hear the thunder immediately because light travels faster than sound. A loud, booming sound indicates that the lightning struck nearby. After this initial loud sound, we can hear prolonged rumbling as the air continues to vibrate, and the extended rumbling of thunder occurs when the lightning strikes at a considerable distance.
