On April 9, 2008, numerous dust plumes blew off the Libyan coast and over the Mediterranean Sea. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image the same day. Although contrasting strongly with the underlying ocean water, the tan plumes are thin enough to allow a view of the land and water surfaces underneath the dust. The plumes blow toward the east-northeast, turning more northward as they move farther off the coast.This dust storm continued a pattern of intermittent storms blowing off the African coast and over the Mediterranean in the early spring of 2008.
More and bigger photos and more information available here, at NASA.