In 2005—2008

Zhejiang Province made an inquiry and evaluation to the debris flows in 42 mountainous counties of the province.It was found that there were 486 debris flows at various scales in the whole province

among which there were about 347 gully debris flows and 139 slope debris flows.From the analyses and studies of debris flow types and their distribution characteristics

gully debris flow is the main type of debris flow

characterized by small scale

large damage

and landslide-collapse changing into debris flow.The distribution of debris flow is mainly controlled by landform

rock nature structure

and precipitation and it is mainly distributed in the volcanic area along big fractures.Debris flows have the obvious bimodal distribution form due to plum rain and typhoon.