A Virginia resident captured a rare cloud formation hovering over the skyline near her home.
Amy Christie Hunter posted a photo of the wave-shaped clouds to Facebook on Tuesday evening. In the image, they can be seen rolling over Smith Mountain near Roanoke.
(MORE: Stunning rainbow cloud caught on video: What to know about the cloud iridescence meteorological phenomenon)The formation is known as the Kelvin-Helmholtz cloud, and is named after the scientists who studied the physics behind them.
(MORE: Strange clouds form over Cape Town, South Africa)The clouds are rare and usually form during windy days when there is a strong vertical shear — meaning the wind is blowing faster at upper levels in the atmosphere compared to the wind at lower levels, causing the clouds to look like rolling waves.
(MORE: Artist creates clouds as art)Weather conditions in the area Tuesday evening included light rain and fog.