User:Runhan Liu/sandbox

Introduction
Vietnam is a Southeast Asian country with a subtropical climate in the north and a tropical climate in the central and southern regions, which are easily influenced by monsoons. The southwest monsoon from May to October each year brings a large amount of rainfall to the exposed areas, namely the north and south. According to Visual Capitalist, Vietnam ranks third globally in terms of the proportion of people most at risk of flooding, with 46% of its 98 million population at risk of flooding.

Vietnam is a country with severe flood disasters. Rainfall, tides, storms, and tropical depressions are natural factors that cause floods. Due to Vietnam's abundant rainfall, with an average annual rainfall of 1500 to 2500 millimeters, heavy rain often leads to flooding in cities with poor drainage systems.

In late October 1999, Vietnam experienced the worst flooding in forty years. Tropical Storm No. 9 (also known as Tropical Storm Eve) first appeared in heavy rain from October 18 to 20, hitting the central provinces of Guangping, Guangzhi, Chengtian Hue, Danang, Guangnan, Guangyi and Heping in Vietnam. The rain was the first in a series of rainstorm events that lasted for 2 to 3 weeks. This tropical storm has caused dangerous (Level II) and extremely dangerous (Level III) floods in several major river basins in central provinces. As of 7:00 am on October 20, the rainfall in the above-mentioned provinces ranged from 100 millimeters to 470 millimeters, exceeding the monthly average level.

As of November 1, the rivers from Yi'an Province to Pingding Province have exceeded the Level III warning. The continuous floods, combined with landslides, have caused serious damage to roads, dams, and infrastructure. At the height of the flood, the heavily affected Hue Street in Chengtian Hue Province was flooded with up to 3 meters of water, and telecommunications services in that area and other parts of the eight central provinces were suspended.

From November 1 to 3, under the influence of strong cold air front and tropical conversion activities, the central provinces from Guangping to Pingding experienced heavy to extremely heavy rainstorm. The combined effect of the South China Sea low pressure zone and the tail of the cold front caused a short-term concentrated rainstorm. Some mountainous areas in Guangnan Province and Chengtian Huhua Province have experienced flash floods, and serious flooding has occurred on the riverbanks from Guangnan Province to Pingding Province.

The rainstorm lasted for 7 consecutive days from November 1 to 7. Due to the large range, concentration of rainfall, 90% of the hilly areas were flooded quickly. The water level of Perfume River and Bo River, the two major rivers in Shunhua, sometimes rose to 8-9m.

As of November 7th, temporary statistical data provided by the Vietnam Central Committee for Flood and Storm Control (CCFSC) estimated that the two week flood had caused approximately 535 deaths. In addition, 604204 houses were affected and 15000 people were evacuated.