Gambar dibawah di snap di Birmingham, Alabama dan ia dinamakan Kelvin-Helmholtz Instability. Berikut adalah explanation dari Wikipedia.
"when velocity shear is present within a continuous fluid, or when there is sufficient velocity difference across the interface between two fluids. One example is wind blowing over a water surface, where the wind causes the relative motion between the stratified layers (i.e., water and air). The instability will manifest itself in the form of waves being generated on the water surface."
Lihat video dibawah sekali.
Ini pula adalah gambar fenomena yg sama yg berlaku di planet Saturn.
Source: 1 & 2