Wave Clouds, Amsterdam Island

Amsterdam Island is just 13 miles long, but the island’s volcano rises 2,844 feet above the surface of the Indian Ocean, high enough to disturb the clouds above it. In the image above, the island creates a wake of lenticular clouds, sometimes called wave clouds when they form this pattern.

The wave clouds were created by wind that hit the island and was forced upward by the volcano. As the air rises, it cools, and water vapor condenses and forms clouds. The air then falls down the other side of the volcano, and the clouds evaporate. This pattern alternates as air flows past the island, creating what resembles the wake behind a ship.

From the ground, lenticular clouds often look like flying saucers or continuous shelves. The image above was taken by the moderate-resolution imaging spectro-radiometer (MODIS) aboard the Terra satellite in December 2005.

Below, the Sandwich Islands in the Southern Atlantic are also creating wakes as low-lying stratiform clouds pass by their volcanic peaks. The size of the wake corresponds to the height of each peak, which range in elevation from 620 feet to 4,500 feet. This image was captured by the MODIS instrument on NASA’s Aqua satellite in January 2004.

Images: 1) Jeff Schmaltz/NASA. 2) Jacques Descloitres/NASA.