霜冻是我省农业生产上主要的灾害之一,尤其在河西地区霜冻危害更加频繁,常常发生晚霜过晚,早霜过早,使作物受害,生产受损。一九七三年五月中旬,由于西伯利亚寒流从北疆入侵河西走廊,五月十五日张掖 Frost is one of the major agricultural disasters in our province. Especially in the Hexi area, the frost damage is more frequent, the night frost often occurs too late, the frost is too early and crop damage and production is impaired. In mid-May 1973, as a result of the cold spell of Siberia invade the Hexi Corridor from the northern border, May 19 Zhangye