Harm of short-term heavy precipitation

Short-term heavy rainfall will bring about a surge in surface runoff, which is easy to cause urban waterlogging and farmland water accumulation, and disasters such as mudslides and landslides are easy to occur in mountainous areas.

What is short-term heavy rainfall?

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. The formation of short-term heavy precipitation requires sufficient water vapor and very strong upward movement.

In summer, especially after the South China Sea summer monsoon and southwest monsoon broke out, the water vapor conditions gradually improved, providing a water vapor basis for the frequent occurrence of short-term heavy precipitation. Therefore, the short-term heavy precipitation in the central and eastern regions affected by the summer monsoon is more active.

At the same time, the rising temperature in summer forms many small and medium-scale convective systems in the extremely unstable energy release, which is also the main reason for the increase of short-term heavy precipitation in summer.

Rain refers to the weather phenomenon that condensed water vapor in the atmosphere falls to the surface of the earth in different ways. The principle of rainfall is that the water on the earth is turned into water vapor after being irradiated by sunlight and evaporated into the air. Water vapor condenses into small water droplets when it meets cold air at high altitude. And then turn into raindrops.

Brief introduction of debris flow:

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.