From NASA: A thick plume of dust blew over the eastern Mediterranean Sea on April 1, 2013, extending northward from Egypt toward Turkey in a giant, counter-clockwise arc. Between Egypt and Turkey, dust clogged skies over Israel, the West Bank, and Cyprus. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this natural-color image of the dust plume the same day.
Outside of the Nile River Valley and Delta, Egypt's land is a dry desert plateau, rich with sand seas that can supply dust storms. In the springtime, hot windstorms can pummel the country. The combination of loose sediments and strong winds make for frequent dust storms, and Egypt lies within a broad band of some of the most prolific dust-producing terrain on the planet.