A giant storm cloud can be seen in the sky above swimmers near Mollymook Beach, south of Sydney, March 5, 2014. (Photo by David Gray/Reuters)

A man flies a kite on the Bund while buildings of Pudong's Lujiazui financial district stand across the Huangpu River as the sun rises in Shanghai, China, on Friday, October 2, 2015. (Photo by Qilai Shen/Bloomberg)

The rising sun illuminates the sky above the spires of a church in Vienna, Austria, November 17, 2015. (Photo by Heinz-Peter Bader/Reuters)

A photographer takes a snapshot of the reflection of balloons as they take off from Balloon fiesta park in Corrales, N.M., near a north diversion channel reservoir Wednesday, October 7, 2015. (Photo by Roberto E. Rosales/Albuquerque Journal via AP Photo)

A snowflake rests on black velvet after a snowfall in Knoxville on Tuesday, January 28, 2014. (Photo by Adam Lau/News Sentinel)