The Yangtze River "No.1 Flood" has been formed! The flood is coming, how should you deal with it?

Recently, heavy rainfall continued to land in the south of China, with heavy rain or rainstorm in parts of central and northern Guangxi, Hunan, northwestern Jiangxi, southeastern Hubei and southern Anhui.

At present, many days of heavy rain have caused many hydrological stations in the Yangtze River basin and the Pearl River basin to exceed the warning water level, and Hunan, Guangxi, Jiangxi and other places have suffered serious floods.

According to the national defense general news, this year's "No.1 flood" in the Yangtze River was formed yesterday, and the national defense general launched a three-level emergency response to flood control.

Characteristics of rainstorm and flood in China

(Image from the Internet)

Flood control safety is an important part of water safety. China is a country with frequent natural disasters, especially rainstorm, flood and its runoff.

Rainstorms are frequent in the rainy season in major river basins, and waterlogging and floods seriously threaten the lives and property of people in the basins, destroy the ecological balance of the basins and hinder the sustainable development of economy and society. Therefore, ensuring flood control safety is a major event related to the national economy and people's livelihood.

(Image from the Internet)

Characteristics of rainstorm and flood

Low seasonality and uneven distribution in time and space.

As the subtropical high moves northward and southward, the rain belt in China also moves northward and southward, showing obvious seasonal characteristics. According to statistics, from April to June in 65438+1October, rainfall in most parts of the country accounted for more than 70% of the annual average rainfall.

● The flood peak is high and large, and the main branches and tributaries are prone to floods.

China's topography is characterized by low in the southeast and high in the northwest, which is conducive to the intersection of warm and humid airflow in the southeast and cold air in the northwest. The steep slope of the ground and poor vegetation conditions lead to rapid confluence and large flood magnitude.

Several major rivers in China have a large area and often encounter floods in main branches and tributaries. There are many incoming waters in the interval, and the flood peaks overlap, which is easy to form a rainstorm and flood with high peak.

(Rongshui County floods, residents travel by boat, picture from the Internet)

● Floods change greatly every year.

The annual changes of floods and flood peak discharge in seven river basins in China are great, especially in the north than in the south.

● Stages and repetitiveness of major floods.

In terms of time, long-term observation shows that in many rivers, the frequency of major floods is high in one period and low in another, and the frequent and low-frequency periods change alternately in stages.

From a spatial perspective, the occurrence of rainstorm and flood in China is closely related to the local weather and topography. All basins and regions that have experienced major floods recently have experienced similar major floods in history.

How did the rainstorm and flood come about?

(Image from the Internet)

China is located in the southeast of Eurasia, bordering the Pacific Ocean in the east, spanning three latitudes of high, middle and low, with obvious monsoon climate characteristics. In winter, the north wind blows, the air is dry, and the climate in most parts of the country is dry. In summer, the south wind blows and the air is humid, and the rainy season mostly occurs during this period.

Frequent rainstorms and floods in China are mainly affected by monsoon. Specifically, there are three reasons:

● Heavy rainfall is concentrated.

Most parts of China are controlled by monsoon climate, and most of the annual precipitation is concentrated in the humid and high temperature period in summer, and most of them appear in the form of heavy rain. The rainfall from June to September accounts for 60% to 80% of the normal annual rainfall.

(Image from the Internet)

● Migration of monsoon rain belt

The seasonal displacement of monsoon rain belt leads to the periodic change of rainfall area. The summer monsoon begins in May and advances from south to north. In the process of advancing northward, there are three relatively stable stages and two leaping stages, corresponding to three rainy seasons, namely, the rainy season in South China, the rainy season in Jianghuai and the rainy season in Northeast China. At this time, the monsoon reaches its strongest.

● Frequent typhoon activities

The rainstorms and floods directly caused by typhoons are mainly distributed in the coastal areas of Guangdong, Guangxi, Fujian, Zhejiang, Jiangsu, Liaoning and other provinces, as well as Taiwan Province and Hainan.

After the typhoon landed on the southeast coast, it generally turned to the north, and the wind speed gradually slowed down, forming a low pressure. If it is combined with the cold air in the north, it may form a large-scale rainstorm and flood, which accounts for a large proportion in the rainstorm and flood in the north.

Types of rainstorm and flood

(Image from the Internet)

Thunderstorm flood

Also known as sudden rainstorm and flood. Due to strong convection in some areas, the airflow with water vapor rises rapidly, resulting in thunderstorms. This kind of thunderstorm usually has the characteristics of short duration, strong rainfall and small rain area, which often causes floods with large momentum, fast fluctuation and small peak height in small watersheds.

(Image from the Internet)

Typhoon, rainstorm and flood

Flood caused by rainstorm caused by typhoon in summer and autumn in southeast coastal areas of Asian continent. Similar to typhoon, rainstorm and flood, the vortex on the mainland is a rainstorm caused by the continuous strengthening of movement.

(Image from the Internet)

Frontal rainstorm and flood

In the flood caused by the rainstorm caused by the intersection of cold and warm air masses, the frontal rain generally lasts for a long time, the rain intensity is small and the precipitation is large. The flood formed by it is often characterized by low peak and large amount in small and medium-sized basins, but there may be large peak and large flood in large basins.

Due to the long duration and large coverage area, storms and floods of combined weather systems often form, causing serious floods.

In case of rainstorm and flood,

What should you do?

(Image from the Internet)

During the rainstorm:

First, try to reduce going out. If you have to go out, you'd better walk in the middle if you want to bypass the place with serious water accumulation.

Second, stay away from high-voltage towers and disconnect wires, and don't touch or approach them.

Three, housing water, should immediately cut off the power supply and gas source.

(Image from the Internet)

When threatened by flood:

First, if there is enough time, we should move to hillsides and highlands in an organized way according to the predetermined route.

Second, when surrounded by floods, use boats, rafts, door panels, wooden beds, etc. Drifting on the water as much as possible.

Third, when it is too late to move, immediately climb the roof, big trees, high walls, do temporary hedging and wait for rescue.

In mountainous areas, if the rainstorm continues, mountain torrents will easily break out. But don't cross the river when flash floods break out, in case it is washed away by flash floods. In addition, attention should also be paid to prevent landslides, rolling stones, mudslides and other injuries.

You should drive very carefully when you are caught in a flood while driving. If flameout occurs, abandon the vehicle immediately.

Pay attention to the disaster in the south!

Friends in the disaster area, pay attention to safety!

Small partners who are not in the disaster area should also pay attention to prevention!

Pay tribute to the people who fought in the front line of flood control!

I hope that the disaster will recede as soon as possible and everyone will be safe!

Editor: Hu Xiaoyu

(This article is based on the fact that knowledge is the original starting point of power. )