Yesterday, Lanzhou Chengguan District is covered by the sand dust. A resident is carrying fully-armed the child walks in the sand dust Lanzhou street. On the same day, Gansu Lanzhou and Minchin, renew, ching t\'ai, Yongdeng and other places to encounter the sand storm weather. In this sand dust synoptic process, the Lanzhou marginal visibility is only 300 meters, the extreme velocity is 11.7 meters/second, is the strong sand storm. Xinhua News Agency Reporter Nie Jianjiang absorbs (This article...