A heavy sandstorm hit the Haixi Mongolian and Tibetan Autonomous Prefecture of northwest China's Qinghai Province on Wednesday, reducing visibility to less than 200 meters in some regions. The sandstorm traveled from west to east, and gradually built up to a strong dust storm by 19:00. The maximum wind speed was 14.9 meters per second. Visibility was reduced to 181 meters in the most heavily affected areas. Traffic slowed down considerably in many areas.