In late December 2015 strong winds carried dust from the Sahara desert westward over the west coast of Africa and over the Canary Islands. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this true-color image on December 25.
The tan dust appears in stark contrast to the deep blue of the Atlantic Ocean. In some areas the dust is so thick that the ocean is completely obscured. The Canary Islands are a volcanic archipelago with steep mountains that can affect the flow of wind. When wind strikes such an immobile object, turbulence is created as the forward-moving wind is re-routed to the side. Immediately behind the leeward side of the object, the air is often still, while wave-like patterns are created in the area of turbulence.
In this image, the islands of Tenerife (west), Grand Canaria, and Fuerteventura (east) have all created patterns by disrupting air flow. Tenerife is home to Mount Teide, an active volcano which rises to 3,718 meters (12,198 feet) above sea level. It is the highest point above sea level in the islands of the Atlantic, and the highest point in Spain. The massive mountain has strongly interacted with the wind which blows from the southeast, leaving a wide dust-free zone on its leeward side.