Trying to keep up the speed after finding Felix' WoGE #477, I present WoGE #478 without waiting for confirmation.
This is more a phenomenon than an occurrence - and recent work suggests that the traditional explanation is wrong.
As always, post a comment with latitude and longitude and write something about the (geologic/geographic/hydrographic) feature in the picture. If you win, you get to host the next one.
Previous WoGEs are collected by Felix on his blog and a KML file.