An astronaut aboard the International Space Station took this photograph of a massive vertical cloud formation--known to meteorologists as cumulus castellanusA--above Andros Island.

These towering columnar clouds are part of the genus cumulonimbus. The cloud name castellanus comes from the similarity to the crenellated towers or turrets of medieval castles. The International Cloud Atlas (World Meteorological Organization) classifies clouds of this type as either Altocumulus castellanus or Stratocumulus castellanus, depending on the base cloud height from which they develop. Regardless of the nomenclature, these clouds develop due to strong vertical air movement typically associated with thunderstorms.

Part of the Bahamas archipelago, Andros Island is divided by large estuaries into three sections. North Andros, Central Andros, and South Andros are each comprised of several smaller islets and cays that are connected by smaller estuaries. Together, Andros Island is the largest in total area (2,300 square miles or 6,000 square kilometers) of all 700 islands in the Bahamas.