Th Landsat 8 satellite spotted a series of "brushstroke-like patterns" in the mouth of the Rokan River on Indonesia's Sumatra island, triggered by a high tide following a full "Strawberry Moon." The Roka River is a 220-mile-long waterway that covers around 170,000 square miles and is the sixth-largest island on Earth. The high tide was at its peak when it was up to 16 feet (5 meters) higher than low tide. The regular tidal bore, which occurs only in estuaries with a high tidal range and a narrow mouth, is responsible for transporting large amounts of sediment back up the river. The shoreline along the north of Halang Island is growing at an average rate of 220 feet per year.