The largest flood occurred in China. Which countries are most prone to flooding?

Guangdong Province in China has faced record rainfall that has caused devastating floods. Authorities have warned of the likelihood of reaching water levels that can only happen once a century.

What is known about flooding in China

The main thing that is now known about the flood:

• Record floods in Guangdong Province in southern China have killed at least four people since Friday and disrupted the lives of more than 110,000 residents living along the main river.
• Water in the Bay River, a tributary of the Pearl River, exceeded 50-year highs, and cumulative precipitation set records for April in several areas.
• Ten people are missing in the cities of Shaoguan and Qingyuan, where rescuers are fighting to rescue trapped residents.
• Helicopters and rubber boats have been deployed in the province to assist affected areas, and in Jinyuan, water levels in some areas have reached the ground floor of buildings.
• The floods caused serious damage to infrastructure, including interruptions to the transport network, evacuations of the population and significant material losses for local residents and businesses.
• Prolonged rains caused avalanches, which led to the disconnection of mobile communications and Internet in some areas, leaving residents isolated and making it difficult to organize rescue operations.

Photo: Xinhua, Getty Images

The largest flood in Libya

Here is the main thing about the flood in Libya:

• The catastrophic flooding in Libya was caused by Storm Daniel, which struck the region on Saturday, September 9, 2023. Heavy rains and floods breached dams and caused widespread destruction. Flood waters peaked in northeast Libya on Sunday, with strong winds reaching 80 kilometers per hour. 
• The city of Derna in northeastern Libya was the most affected. Several large bridges were demolished by flood waters, and many multi-storey buildings of the city located on the banks of the riverbed collapsed.
• Satellite images show that entire neighborhoods were washed away, and many bodies were swept out to sea.
• The death toll has exceeded 6,000 people, and at least 10,000 people are missing. 
• Many hospitals in Derna were demolished and morgues overflowed.
• Other areas close to Derna, including the city of Al-Bayda, were also severely affected.

WHO has deployed humanitarian aid in the affected areas. According to her estimates, up to 1.8 million people were affected by the torrential rain, and some hospitals were damaged and even “wiped off the face of the earth”. The Libyan government has declared three days of mourning in all affected cities.

Why do floods happen?

Floods can occur for various reasons, here are some of the main ones:

• Heavy rains: One of the most common causes of flooding is heavy or prolonged rains. When there is more precipitation than the earth can absorb or rivers and streams can carry out, this leads to a spill of water on the terrain.
• Snowmelt: In regions with cold winters, snowmelt in spring can lead to floods. If the snow melts too quickly or a sudden warming occurs, it can overflow rivers and cause them to flood. 
• Storm surges:Coastal areas are prone to flooding as a result of storm surges that occur during hurricanes, typhoons and tropical storms. Such storms can push large volumes of water inland, causing coastal flooding. 
• Flash floods: Flash floods are often the result of intense rainfall over a short period of time. They can occur in areas with steep terrain, in cities with poor drainage systems, or near forest fires that have stripped the landscape of vegetation.
• Ice jams: In cold climates, ice can accumulate on rivers, forming ice jams. These congestion can block the flow of water, which leads to its overflow and flooding of nearby areas when the congestion eventually breaks through.
• Human activity: Human activity can contribute to the occurrence of floods. Deforestation, urbanization and changes in natural drainage systems can increase the risk of flooding, as they reduce the ability of the earth to absorb and divert excess water.
• Dam or dam failure: Floods can occur when man-made structures such as levees and dams are destroyed. If these structures are not properly maintained or overflowed with a large volume of water, they can crack, which will lead to catastrophic flooding in the lower reaches of the river.
• Climate change: Climate change can exacerbate floods by changing weather patterns and increasing the frequency and intensity of extreme weather events such as heavy rains and hurricanes.

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Which countries in the world are most prone to floods?

It is difficult to unambiguously determine the rating of the most flood-prone countries, since floods can occur in different forms (riverine, coastal, flash floods) and with different frequency. However, it is known that some countries are particularly prone to floods due to their geographical and climatic features. 
Some of these countries include:

• Bangladesh is often called one of the most flood-prone countries in the world. This South Asian country experiences frequent and severe floods due to its unique geographical location and monsoon climate. Bangladesh is crossed by numerous rivers, including the Ganges and Brahmaputra, carrying water from the Himalayas. During the monsoon season, heavy rainfall in the region, combined with melting snow in the mountains, leads to a significant amount of water entering these rivers.
• India: Some areas of India, especially in the Ganges and Brahmaputra basins, as well as on the east and west coasts, are prone to flooding during the monsoon season and as a result of cyclonic activity.
• Vietnam: Vietnam is prone to frequent river and coastal flooding, especially in the Mekong Delta region, due to heavy rainfall, typhoons and rising sea levels.
• Indonesia: Indonesia’s nature makes it prone to both river and coastal flooding. Floods are especially frequent in the capital, Jakarta.
• China: China is prone to river and flash floods, often caused by heavy rains and snowmelt, especially in areas near the Yangtze River, the Yellow River and in the southern provinces.
• Pakistan:Pakistan is prone to river flooding, especially in areas near the Indus River, due to heavy monsoon rains and snowmelt.
• Philippines: The Philippines is prone to both coastal floods associated with typhoons and flash floods caused by heavy rains during the wet season.
• Nepal: Nepal is at risk of river flooding, mainly due to mountainous terrain and heavy monsoon rains.
• USA (in particular, areas along the Mississippi and Missouri Rivers): Significant river flooding is observed in the USA, especially in areas along the Mississippi and Missouri Rivers, caused by heavy rains, snowmelt and the destruction of dams.

It should be noted that Libya is usually not considered a country with a high risk of flooding, primarily because it has a dry desert climate with low average annual precipitation. Most of Libya is occupied by the Sahara Desert, which is one of the driest and hottest regions in the world. As a result, the country experiences arid and semi-arid conditions with infrequent and minimal rainfall in most areas.
However, it is important to note that in Libya, as in many arid regions, flash floods occur from time to time. The risk of their occurrence is increased:

• Sporadic precipitation: Although Libya is mostly an arid country, there are areas on the Mediterranean coast and in the northern part of the country where precipitation falls irregularly, especially during the winter months. Heavy rains in these areas can lead to flash floods, as the dry desert soil is not able to absorb water quickly.
• Poor drainage infrastructure: In some urban areas, poor drainage systems can exacerbate the effects of heavy rains, leading to local flooding. 
• Topography:The terrain in some areas of Libya, for example in the Jabal Akhdar region, can lead to flash floods when heavy rains flow down steep slopes into valleys.

The most catastrophic flood in world history

One of the most catastrophic floods in world history is the 1931 flood in China. A vast area of China was affected, with the Yangtze River Basin and the Huai River Basin most severely affected.

Reasons:

• Heavy rains: The flooding was caused by a number of factors, including prolonged and heavy monsoon rains.
• Melting snow: Melting snow in the mountains, especially on the Tibetan plateau, has increased the volume of water flowing into rivers.
• River abundance: The Yangtze River, China’s longest river, and its tributaries, including the Yellow River, have overflowed their banks.

Effects:

• Estimates of the death toll from the 1931 flood In China, they vary greatly, but it is believed that from 1 to 4 million people died. This variation in estimates is due to difficulties in accurately documenting victims during and after the flood.
• Millions of people were forced to leave their homes, and entire villages and towns were flooded. The flood led to great suffering, including starvation and disease among the survivors.
• Floods inundated vast agricultural areas, leading to crop failures and food shortages.
• Homes, infrastructure and transport networks were severely damaged or destroyed.

What should I do if I find myself in a flood zone?

If you find yourself in a flood zone, here’s the most important thing to know:

• If the local authorities have issued an evacuation order, follow it immediately. 
• If you cannot evacuate and are trapped in a building, go up to the highest level or to the top floor. Take the necessary things and documents with you.
• Do not walk, swim or drive a car through flood waters. Remember that just six inches of moving water can knock you down, and one foot of moving water can carry away your car.
• Stay away from floodwaters as they may be contaminated with sewage, chemicals or debris. 
• Stay tuned for weather updates from local authorities, weather services or news agencies. Pay attention to flood alerts and warnings.
• Stay in the car if it is trapped in fast moving water. Get out on the roof if the water rises inside the car.
• Do not return to the flood-affected area until the local authorities declare it safe. Flooding can persist even after the rain stops.

The author of the cover photo: Jamal Alkomaty/AP

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Yulia Yanukovych Editor-in-Chief

I am responsible for the work of the editorial office. I write expert interviews and guides.

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