The Cape Verde Islands, located about 350 miles off the coast of West Africa, are no stranger to dusty skies. Strong winds blowing west across the Sahara Desert can carry dust and sand far over the Atlantic Ocean throughout the year.
In this NOAA-20 satellite image, seen Dec. 9, 2018, we can see a faint brown cloud of dust over the Cape Verde Islands against a backdrop of mostly clear skies. While the islands are sometimes shrouded in dust plumes far thicker than the one shown here, this is the first dust cloud seen over Cape Verde in recent weeks.
During winter, dusty skies are common around West Africa, thanks to a dry trade wind called the harmattan, which blows from the east or northeast from late November through mid-March. Strong harmattan winds can create large sandstorms over the Sahara and carry dust out over the Atlantic.
This image was captured by NOAA-20's VIIRS instrument, which scans the entire Earth twice per day at a 750-meter resolution. Multiple visible and infrared channels allow us to obtain high-resolution satellite imagery of clouds, storms and atmospheric aerosols, such as dust and sand.