How can central Vietnam reduce flood damage?

Editor’s note: Reviewing the recent storms and floods, Associate Professor Vu Thanh Ca of the Hanoi University of Natural Resources and Environment shared his analysis with Tuoi Tre (Youth) newspaper, explaining why central Vietnam has suffered unusually severe storms and floods.

The commentary was translated from Vietnamese and edited by Tuoi Tre News for clarity and coherence.

A particularly harsh 2025 rainy season

The year 2025 has been exceptional, with unusually warm sea temperatures across the East Vietnam Sea.

On November 20, measurements showed average sea-surface temperatures above 29 degrees Celsius across the basin.

Typically, mid-November temperatures in the central parts of the East Vietnam Sea range from 26 degrees Celsius to 28 degrees Celsius.

Surface temperatures remained high through the summer and cooled only slightly in the fall.

This persistent heat fueled the formation of strong storms and extreme rainfall across Vietnam.

Central localities, in particular, were repeatedly hit by intense storms that brought flooding and landslides.

The region’s rainy season usually begins with powerful storms and northeast monsoons in late autumn and early winter, or from September to December.

During this period, sea temperatures remain warm, boosting evaporation and loading the atmosphere with moisture.

Storms form over warm tropical waters where moist air rises and condenses under specific atmospheric conditions, creating low-pressure systems that intensify into tropical depressions and, if favorable conditions persist, into full storms.

As these storms move into central Vietnam, they carry enormous amounts of moisture inland, producing heavy rainfall.

Meanwhile, the northeast monsoon brings additional moisture from the sea.

When these moist air masses reach land, terrain and residual surface heat force the moisture upward, forming convective clouds.

As water vapor condenses, latent heat release further strengthens vertical air movement and upper-level wind convergence, resulting in more rainfall.

Along the eastern slopes of the Truong Son range, steep terrain forces moist air upward even more sharply, producing extreme rainfall.

Central Vietnam’s short, steep rivers quickly funnel run-off toward low-lying areas, causing rapid flooding.

During intense storms, flash floods can form suddenly in river sections, posing severe risks to people and infrastructure.

Heavy rainfall on steep slopes can also trigger landslides.

Possible measures to reduce flooding, losses

Several measures should be considered to reduce flooding and related damage in central Vietnam.

First, improving rainfall forecasting is essential.

Investment in personnel and modern forecasting technologies would allow more accurate predictions, helping authorities operate reservoirs effectively, prepare for incoming floods, and evacuate residents from high-risk areas.

Reservoir flood-control capacity should be enhanced by reviewing and revising operating procedures, including coordinated operations among multiple reservoirs, to maximize flood mitigation.

Rivers and drainage channels must be dredged and cleared, and illegal structures blocking flood pathways should be removed to ensure rapid water discharge.

Buffer zones that can temporarily store water should be developed to protect critical areas from inundation.

Housing should be designed or retrofitted to withstand floods—such as the use of floating homes.

Public infrastructure, including hospitals, schools, and government facilities, should be reinforced to remain operational during floods and serve as shelters for evacuees.

Authorities should continue identifying areas at high risk of flash floods and landslides and relocate residents from these zones.

Protecting and restoring natural forests is especially crucial to reducing flood severity.

The influence of La Niña, climate change

La Niña, a major climate pattern known to increase storm and rainfall activity, emerged over the Pacific in October 2025.

Its presence is expected to intensify storm frequency and rainfall.

Climate change is also warming the oceans.

Studies indicate the East Vietnam Sea has been heating rapidly; between 2003 and 2017, sea-surface temperatures rose by about 0.31 degrees Celsius per decade.

Warmer waters boost evaporation, increasing atmospheric moisture and contributing to stronger storms and heavier rains.

As a result, both the Mekong Delta and central Vietnam are among the regions most affected by climate change.