Explaining the cause of record rain in Hue, never recorded in Vietnam

Heavy rain over the past two days in the Central region has caused many rivers to exceed alert level 3, and many places in Hue city have recorded record rainfall, exceeding historical values.

National Academy stele submerged in flood water.

Speaking on VTC News, Mr. Mai Van Khiem, Director of the National Center for Hydro-Meteorological Forecasting, said that over the past two days, many areas in Hue city and Da Nang city have experienced heavy rain, floods on many rivers have exceeded alert level 3, causing widespread flooding.

The water level on the Bo River at Phu Oc station ( Hue City) reached 5.25 m, exceeding the historical value in 2020 (5.24 m).

At the monitoring station in Nam Dong (Hue City), the rainfall from 7 p.m. on October 26 to 7 p.m. on October 27 reached 1,085.8 mm. This is a rainfall amount exceeding historical value and never recorded in Vietnam.

Bach Ma (Hue City) is also one of the places that recorded very heavy rainfall. In less than 24 hours, from 7am on October 27 to 3am on October 28, the rainfall at Bach Ma peak station reached 994.2 mm. Mr. Khiem said that not only in this heavy rain in Bach Ma, there was sudden rain, but in other heavy rains, Bach Ma was always one of the rainiest areas in Hue City as well as the whole country.

"According to my observations, the rainfall in Bach Ma is many times higher, 4-5 times higher than in neighboring areas. The rainfall in Bach Ma always reaches extreme values ​​higher than the rain gauges in Hue City or Da Nang City," said Mr. Khiem.

The main reason is due to the terrain factor, Bach Ma point is located in the Truong Son range, right on the edge of the East Sea, at an altitude of over 1,400m. When the humid air mass from the sea blows in (especially when there is a weather combination of low-level cold air, tropical convergence zone and humid East wind zone above active), it creates a humid convergence zone and then there is a "forced elevation of the terrain" activity, that is, the humidity converges and rises high, causing the moisture to condense strongly, creating very heavy rain on the spot.

Mr. Mai Van Khiem said that the cause of this flood is the combination of low-level cold air, the tropical convergence zone rising from the South, along with strong humid easterly winds at an altitude of 1,500 - 5,000 m. This is a typical situation that causes very heavy rain in the Central region, and most of the prolonged, especially heavy rains in the region are caused by this weather combination.

It is forecasted that in the next 2 days, the cold air complex, tropical convergence zone, and easterly winds will still be active. Therefore, from now until the end of October 29, from South Quang Tri to Da Nang City and the East of Quang Ngai Province, there will be heavy to very heavy rain with common rainfall in South Quang Tri and the East of Quang Ngai Province of 150-300 mm, locally over 500 mm, Hue City and Da Nang City ranging from 200-400 mm, in some places over 600 mm.

From Ha Tinh to Northern Quang Tri, there will be moderate rain, heavy rain and thunderstorms, with common rainfall of 80 - 150 mm, and locally very heavy rain over 300 mm.

Risk of heavy rain, rainfall exceeding 200 mm in just 3 hours.

From the night of October 29 and October 30, when the east wind tends to decrease, Ha Tinh to Da Nang city and the east of Quang Ngai province will have moderate rain, heavy rain and thunderstorms, rainfall ranging from 50 - 100 mm, in some places very heavy rain over 200 mm.

From the night of October 30, heavy rain tends to decrease in the South and gradually move to the North of the Central region.

According to Mr. Khiem, from now until the end of 2025, there will be about 2-3 storms/tropical depressions operating in the East Sea and about 1-2 storms affecting our country.

From now until about the first half of December 2025, moderate and heavy rains may continue to appear in the Central region, concentrated in the area from Ha Tinh to Da Nang, Khanh Hoa and the eastern provinces from Quang Ngai to Dak Lak.

PV (synthesis)

Source: https://baohaiphong.vn/ly-giai-nguyen-nhan-mua-ky-luc-tai-hue-chua-tung-ghi-nhan-o-viet-nam-524862.html