The influence of the northeast trade winds on the island of Oahu is apparent by the formation of clouds on the windward slopes of the Koolau Range in northeastern Oahu and by a highly reflective island wake (created by the current flow of water around the island) off the southwest coast of the island. A broad, cultivated, northwest-southeast-aligned valley connects the Koolau Range with the higher paralleling Waianae Range along the southwestern side of Oahu. Kaala Mountain [4046 feet (1233 meters)] in the Waianae Range is the highest elevation on Oahu. Pearl Harbor, Honolulu, Honolulu International Airport, and Diamond Head Crater are discernible along the southern coast of the island.