What is easy to cause short-term heavy precipitation in mountainous areas?

Short-term heavy precipitation is easy to cause mountain torrents, which may lead to landslides and mudslides.

Short-term heavy rainfall means that the rainfall in a certain place exceeds 20 mm within 1 hour. Short-term heavy precipitation is a strong convective weather. This kind of weather usually lasts for a short time and will clear up soon. It usually appears in the summer afternoon in the northern region. Hazard: only for cities with poor drainage, because the time is short and the intensity is high. Main hazards: excessive water accumulation on the road surface.

In summer, due to the high temperature and large evaporation, a large amount of water vapor rises and condenses into clouds; At the same time, the cold air in the upper layer will drop, and they will continue to rise after being heated, so as to circulate and form a large cumulonimbus cloud. Cumulonimbus clouds will produce short-term heavy precipitation (convective rain), sometimes accompanied by strong winds, thunderstorms, hail and even tornadoes and other bad weather.

Debris flow refers to a special torrent containing a large number of solid substances such as mud, sand, stones and boulders, which is produced in valleys or hillsides due to precipitation (heavy rain, glaciers and snow melt water). The process of collecting water and sand is very complicated and is the product of various natural and/or human factors.

Debris flow has the characteristics of strong suddenness, fast velocity, large flow, large material capacity and strong destructive power. Debris flow often destroys roads, railways and other transportation facilities and even villages and towns, causing huge losses. Debris flow is a torrent formed by saturated dilution of soft soil mountain containing sand and gravel by rainstorm and flood, and its area, volume and flow are large, while landslide is a small area of diluted earth mountain.

Hazards of debris flow:

The main hazards of debris flow are destroying towns, enterprises, factories, mines and villages, causing human and animal casualties, destroying houses and other engineering facilities, and destroying crops, trees and cultivated land. In addition, mudslides sometimes block rivers, which not only hinder shipping, but also may cause floods.

The factors that affect the intensity of debris flow are debris flow, velocity and discharge, among which the flow has the most important influence on the degree of debris flow disaster. In addition, various human activities have intensified the role of these factors in many aspects and promoted the formation of mudslides.