The sky turned dark, resembling a nightmare for coastal residents, even though it was only 10 AM.
This strange phenomenon occurred over the past weekend in Alabama, USA. A long line of gigantic, rolling waves appeared on the horizon, slowly sweeping forward. Residents of Alabama, both terrified and astonished, captured the scene and sent it to the local meteorological station. The police and authorities’ hotlines were continuously overwhelmed. The most pressing question was, of course, “What does the tsunami-like waves in the sky mean? Could it be a sign of disaster?”
However, experts believe that these tsunami-shaped clouds are a classic example of “Kelvin-Helmholtz Waves,” which are formed when two layers of air collide. Whether observed in the sky or beneath the ocean, this type of turbulent motion occurs when a faster-moving “liquid” layer slides over a slower-moving, denser layer.
In this case, the lowest atmospheric layer (50 – 100), which is close to the ground, exhibited higher stability compared to the upper atmospheric layers on that morning. As long as the ground temperature does not rise due to heat from the sun, the lower layer remains more stable than the upper layers. Kelvin-Helmholtz waves occur when winds pass through these air layers, destabilizing the upper part of the bottom layer and adding air to the oscillating layers. The result is that the stable air layer is lifted, cooled, and densified. To a certain extent, this entire process becomes visible, creating bizarre shapes in the sky.
Similarly, water waves form when the upper “liquid” layers (such as air) move faster than the lower “liquid” layers (like water). When the difference in speed between the wind and water reaches a certain threshold, waves break and create a series of Kelvin-Helmholtz formations (named after the two German scientists who discovered this phenomenon).
Previously, meteorologists had also collected numerous images of strange clouds caused by Kelvin-Helmholtz waves.
