Affected by the eastward cold air currents from the northwest China, the eighth dust storms formed in the north on April 12. Parts of Gansu province was engulfed by the sandstorms and "black winds" at the speed of 25 meters per second. Dust storms also hit parts of Ningxia, Inner Mongolia, Xinjiang and Qinghai. It is forecasted that the storms may stop during the mid-day of April 14...