Vietnam: Heavy rainfall, strong winds, flooding, and landslides forecast across southern and central Vietnam through Oct. 30

Event

Additional rounds of heavy rainfall, strong winds, flooding, and landslides are possible across southern and central Vietnam through at least Oct. 30. The Vietnam National Centre for Hydro-Meteorological Forecasting has warned of moderate rain across Quang Nam and Quang Ngai provinces while moderate to heavy rain is likely across the Central Highlands, Southeast, and Mekong River Delta regions as well as Binh Dinh, Khanh Hoa, Ninh Thuan, and Phu Yen provinces through Oct. 25. Heavy to very heavy rain is forecast from Thua Thien Hue to Binh Thuan provinces and across the Central Highlands and Southeast regions Oct. 26-27. Tornadoes, lightning, hail, and strong winds are possible across the affected areas.

Flooding has been reported across Quang Ngai Province, resulting in one death and almost 11,000 houses flooded. Authorities have evacuated at least 965 households from flooded areas in Binh Son District, 50 households from Duc Pho Town, and 21 households from Tra Bong District. Floodwaters have receded in some areas; however, additional rainfall could exacerbate current conditions.

Hazardous Conditions
Additional rounds of sustained heavy rainfall could trigger further flooding in low-lying communities near rivers, streams, and creeks. Additional urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall.

In Binh Dinh Province, Highway 1 is impassable in Tran Quang Dieu Ward, Quy Nhon City due to flooding while a portion of the Ngo La Bridge on National Highway 19C in Canh Vinh Commune, Van Canh District has collapsed. In Huong Tra Commune, Tra Bong District, Quang Ngai Province, the Eo Chim Pass to Tra Nham is impassable due to landslides, isolating around 490 households in Tra Huynh, Tra Van, and Ca Dam villages.

Additional landslides cannot be discounted in hilly or mountainous areas, especially where heavy rainfall has saturated the soil. Forecast models indicate heavy rainfall of 15-25 cm (6-10 inches) is likely across Binh Dinh to Ninh Thuan provinces as well as the South Central Highlands Region, while 10-20 cm (4-8 inches) of rainfall is likely over the rest of the affected area Oct. 26-27. Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Severe weather could also trigger flight delays and cancellations at regional airports. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. If strong winds trigger hazardous sea conditions, authorities may temporarily suspend port operations or close beach fronts along the South China Sea. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Health
Although a secondary concern, the threat of disease outbreaks cannot be discounted in the coming days and weeks. Backflow from drains that have mixed with floodwaters can become trapped in open areas when inundations recede. These stagnant pools often become a breeding ground for mosquitoes and bacteria, increasing the incidence of insect- and waterborne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.

Advice

Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments prior to travel. Make allowances for localized travel delays, as well as potential supply chain disruptions, where flooding has been forecast. Do not drive on flooded roads. Charge battery-powered devices in the case of prolonged electricity outages. Observe strict food and water precautions, as municipalities could issue boil water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks. Keep any necessary medications in a waterproof container.

Resources

Vietnam National Centre for Hydro-Meteorological Forecasting