At first glance, it seems that this image is the result of working in a photo editor, but this is a real shot without any processing.
Looming over Mount Pisgah in Asheville, North Carolina, these bizarre tubular clouds are due to the Kelvin-Helmholtz instability. It occurs when there is a shift between the layers of one medium, or when two contacting media have a speed difference. The two air currents have different properties and instability arises between them. The differences are expressed not only in the velocities of the two horizontal layers, but also in temperature and density. As a result, eddies appear at the border that resemble waves on the sea. Such clouds are often observed in the mountains and near the sea coasts, as well as during the passage of a warm front. In the image, air is pushed up the steep mountain slopes, forming clouds in a process known as "orographic rise." Then the swift winds collide with these newly formed clouds,and as a result of the Kelvin-Helmholtz instability, they twist like giant ocean waves.
A typical example of such instability is the generation of waves on the water surface by wind. The instability appears at different heights - in stratocumulus, altocumulus, and cirrocumulus. The clouds are named after Lord Kelvin and Hermann von Helmholtz, who studied the dynamics of two fluids of different densities. These clouds are also called Van Gogh's clouds - in his painting "The Starry Night" you can see similar whimsical curls. It is likely that the artist was inspired by these rare clouds.
