20 Oct 20 VNExpress Source Experts believe flooding in central Vietnam is a result of complex, future "new normal" weather patterns."According to our global assessment of current meteorological conditions, Vietnam is experiencing the worst weather impacts in the world at present," said Grahame Madge, a spokesman for U.K. Met Office that provides critical weather services and world-leading climate science.
Since October 6, the central region of Vietnam has suffered from torrential downpours that triggered severe flooding. Storm Linfa, which hit on October 11, and Storm Nangka, a day later, worsened conditions and caused landslides in different parts of the region.
Storm Linfa grew from a tropical turbulence that, combined with a cold spell, had caused days of heavy rains in the region earlier .
At least 102 people have died, while 26 remain missing in central Vietnam.
Fatalities include many landslide victims - two workers buried at a hydropower plant in Thua Thien-Hue on Monday last week, and 13 others on a rescue team dispatched to find the missing workers and themselves hit by a landslide the next day. Another landslide in Quang Tri buried 22 people Sunday morning. Searches are ongoing for 15 victims of the first catastrophy.
As of Monday evening, Ha Tinh, Quang Binh and Quang Tri provinces had 166,780 households submerged in floodwaters, with 28,900 households with 90,900 residents evacuated.
The National Center for Hydro-Meteorological Forecasting said heavy downpours are likely to continue until Wednesday.
Madge told VnExpress it is likely to see further exceptional rainfall across central parts of Vietnam in the next two to three days and it is possible that some locations could experience as much as 1200 mm of rainfall in this period. Rainfall of 180 mm per day is considered heavy.
"This is being fueled by an active monsoon trough with the potential for weak tropical cyclone development, further boosting total [rainfall]."
"Longer term, the potential development of a stronger tropical cyclone in the South China Sea [which Vietnam calls East Sea] may push the monsoon trough south of Vietnam, allowing drier conditions to prevail," he predicted.
Speaking of reasons for the floods in central Vietnam, Kei Yoshimura, professor of Environmental Studies, Department of Natural Environmental Studies at the University of Tokyo pointed out Storm Linfa and Storm Nangka.
"The biggest reason is Linfa, which directly hit central Vietnam on October 11 and caused an unusual amount of rain, and the more unusual is that Typhoon Nangka hit Vietnam straight after."
That is rare, he said, but it may have happened by chance since in the past 18 years, 53 typhoons approached Vietnam, at rate of 1-5 per year, he said, citing data from Digital Typhoon, a database of about 200,000 typhoon images dating back to 1979 and typhoon best tracks from 1951 searchable by date, name, location, cloud patterns, and so on.
The amount of rain that fell from October 6 to 13 was two to six times higher than normal.
Ha Tinh Province received 150-400 mm during this period, Quang Binh 400-500 mm, Quang Tri 800-1,500 mm, Thua Thien Hue 1,300-2,000 mm, Da Nang City 1,100 mm, Quang Nam 900-1,200 mm, and Quang Ngai 600-800 mm.
The entire central region suffered from severe flooding for days, with over 135,000 houses submerged under 0.3-4 meters of water, according to the national forecast center.
Brian Eyler, director of Asia Program at U.S.-based Stimson Center, said: "I'm afraid these sudden floods will become the new normal for Vietnam's central coast areas and those living in these impact zones should prepare for such future storms. Stimson Center is a nonprofit, nonpartisan think tank that aims to enhance international peace and security through a combination of analysis and outreach.
With rising seas, floods penetrate farther inland than ever before when they pass over the East Sea, he said, adding that sea level rise and intense storms would work together to add a multiplier effect to the devastation, and that this phenomenon would continue to dog the coastline, worsening each year.
He suggested Vietnam consider building sea walls and relocating coastal communities, ensuring livelihoods remain unaffected.
However, he went on to admit it would be a hard task for Vietnam, and that the country would "either need a creative response that it can teach to others around the globe or the country will muddle from one annual flood disaster to another."
This is because 30 percent of Vietnam's 96-million population lives in a coastal flood zone, with the majority relying on coastal economic activities like fishing or tourism.
Meanwhile, building sea walls is a costly option and can also be risky if not completed to the very highest standards, he stressed.
Yoshimura said to cope with this situation in the long term, a flood warning system should be implemented in Vietnam.
"Thanks to advancements in satellite observation and numerical prediction, it is now possible to predict flash floods more than 24 hours ahead. It may help evacuate people to safety."
Climate change may have affected typhoon and rainfall characteristics, and therefore previous experiences may not be so useful in coming decades, he maintained.