File:Cloud vortices off Heard Island, south Indian Ocean (MODIS 2016-05-07).jpg

English: Swirling eddies of wind drew delicate pictures in the clouds behind Heard Island in early May 2016. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Aqua satellite captured this true-color image on May 3 as it flew over this remote section of the south Indian Ocean.

Heard Island is a sub-Antarctic island, sitting about two-thirds of the way from Madagascar to Antarctica, and about 4,000 km (2,485 mi) southwest of mainland Australia. It is about 40 km (25 mi) wide from east to west and 20 km (12.5 mi) from north to south. The topography is rugged and is dominated by a tall volcano, Big Ben, which reaches 2,745 m (9,005 mi) in elevation.

Heard Island lies in the "furious 50s" a region of persistently strong winds near 50 degrees south latitude. The strong winds and frequent cloud cover often combine to paint fascinating designs in the clouds on the leeward side of the island.

When strongly blowing wind slams into the tall and immobile Big Ben, the flow is suddenly interrupted. Instead of moving straight forward, much of the wind must push around the volcano, creating a turbulent flow of swirling eddies behind the island. When cloud cover is heavy, the movement of the turbulent air is clearly written in the clouds and easily seen from space.