August 21, 2013
Photographer: Zsuzsanna Agnes Nagy
Summary Authors: Zsuzsanna Agnes Nagy; Jim Foster
This strange cloud, looking like a corkscrew in the sky, was observed at sunset over Polgardi, Hungary, on July 24, 2013. Actually, it's a jet contrail. Perspective makes it appear to be spiraling straight down. Instead, it's heading west in the direction of the distant horizon. Both the contrail and lens shaped cloud at top left (not a contrail) are high enough (likely over 25,000 ft or 7,620 m) to be illuminated by the Sun, which is now well below the horizon. Atmospheric turbulence and the angle of solar illumination produced the twisted appearance. The earlier formed portion of this contrail (center) has now spread out considerably.