Disasters and regional risks of debris flow in Zhaotong Prefecture,Yunnan Province,China

Zhaotong Prefecture has the area of 22,434km², where there are more than 330 debris flow ravines, with the average spatial density of 14.7 spots per 1,000km². According to the method of evaluation on the regional risk of debris flow, this study has come to the following conclusions: Qiaojia County-risk grade V; Yongshan, Yanjin, Ludian, Daguan, Weixin and Zhenxiong counties-risk grade III; Yiliang, Suijiang-Shuifu and Zhaotong City-risk grade II. Compared with the field investigation, the result is satisfied.