Meteorologists warn Vietnam to brace for intensifying heat waves

Deputy Director of the center, Hoang Phuc Lam, indicated that the El Nino phenomenon is expected to subside between April and June, making way for La Nina from July to August.

Consequently, heightened heat waves are projected for this year, potentially surpassing historical averages.

El Nino, characterized by elevated sea surface temperatures in the central and eastern Pacific Ocean, typically induces reduced rainfall in many regions of Vietnam, particularly the Central Highlands and southern areas.

This often results in drought conditions, affecting water supply for various purposes including domestic use, agricultural irrigation, and hydropower generation.

Notably, the 2015-2016 El Nino event, one of the most intense on record, triggered severe droughts across Vietnam.

Moreover, El Nino events typically coincide with above-average temperatures, leading to widespread heat waves across the country.

In contrast, La Nina, marked by cooler-than-average sea surface temperatures in the central and eastern Pacific Ocean, generally brings opposite effects to Vietnam, including increased rainfall, particularly during the monsoon season.

On average, Vietnam experiences about 15 heat waves annually, with temperatures soaring above 35 degrees Celsius.

This year, heat waves are forecast to occur from April to July in the northwest, peaking between May and June.

In the northeast and Red River Delta, including Hanoi, they are expected from May to August, with the peak occurring between June and July.

The central region, with its diverse terrain, will witness heat waves from April to August, peaking between June and July in the Thanh Hoa - Thua Thien Hue area and from May to August, peaking in July in the Da Nang - Khanh Hoa area.

In the southern region, including Ho Chi Minh City and the Mekong Delta, heat is expected from February until May, peaking from now until the end of April.

Regarding rainfall patterns, Lam predicted the onset of seasonal rains in the north starting April.

However, the Central Highlands and southern areas may experience delayed rainy seasons, beginning from June, with the southwest monsoon exhibiting greater activity than usual.

Towards the end of the year, heavier rains are anticipated in the central region, particularly from September to November.

Due to the lingering impact of El Nino from last year, many rivers in the central region and Central Highlands have seen a significant decrease in flow, ranging from 15-55% below the historical averages.

Consequently, droughts and water shortages are forecast from April to June in provinces like Binh Thuan, Kon Tum, Gia Lai, Dak Lak, Dak Nong, Lam Dong, and from May to August in Quang Nam, Quang Ngai, Phu Yen, Khanh Hoa, and Ninh Thuan.

Lam also noted that this year's flood season is likely to be delayed in the north, leading to lower water resources in rivers and lakes.

Specifically, the water levels in the Da River, home to the country's largest hydropower plant system, are expected to be 30-50% below average, a 5-10% increase compared to 2023.

Additionally, tropical depressions in the East Sea are predicted to be fewer than the historical average, with storms primarily occurring in the latter half of the season due to the influence of La Nina.

Pham Thi Thanh Nga, Head of the Meteorology, Hydrology, and Climate Change Science Institute, underscored the significant impact of the rapid transition from El Nino to La Nina on Vietnam's weather patterns.

If La Nina manifests towards the year's end, expect more frequent storms, heavy rains, floods, and flash floods in the central region, as well as off-season rains in the south.

Nga also pointed to the increasing occurrence of urban flooding amidst rapid urban development.

In 2023, Vietnam encountered 20 heat waves, exceeding the historical average by five occasions.

On May 7 last year, temperatures soared to 44.2 degrees Celsius in central Nghe An Province, marking the highest temperature on record. Summer 2023 also saw many large hydropower reservoirs fall below dead water levels, leading to widespread power shortages in northern and central regions.