Vortex cloud, Wallops Island, VA

The photo below is from a NASA study on the wake vortices of aircraft. Here, the vortex phenomenon is made observable with the use of colored smoke. The formation occurs naturally in many diverse scenarios — tornadoes, hurricanes, and cyclones being obvious cloud-related examples.

(Source: matadornetwork.com/bnt/60-insane-cloud-formations-from-around-the-world-pics/)