This impressive (and seemingly endless) roll cloud was spotted from a ship en route from Paranagua, Brazil to Montevideo, Uruguay. The image was taken by Capt. Andreas M. van der Wurff and chosen as the Earth Science Picture of the Day for February 29, 2012.

The Captain explains:

“A cloud feature like this isn’t something you would want to run into on the open sea or on a crowded highway, but roll clouds (arcus cloud) aren’t necessarily a presage of severe weather. They most often form along the leading edge of a mature thunderstorm in the relatively cool air associated with the storm’s downdraft; however, they’re detached from the storm itself and may be seen to roll or tumble along their horizontal axis.”

 

This isn’t the first time a roll cloud has been featured as a POTD (see here and here) or in a standalone post. If you enjoy looking at various cloud formations, be sure to check out the ‘clouds‘ tag on the Sifter!