Vietnam: Adverse weather forecast across northern mountaonous regions through at least early Dec. 13

Severe weather is forecast across moutainous parts of northern Vietnam through at least early Dec. 13. As of Dec. 11, the Vietnam National Center for Hydro-Meteorological Forecasting (NCHMF) has issued a warning for thunderstorms, heavy rainfall, strong winds, lightning, and possible tornadoes across the affected area. Moderate to heavy rainfall amounts of 2-4 cm (0.8-1.6 inches) with ioslated higher amounts of over 6 cm (2.4 inches) are expected across the region late Dec. 11-12. Rainfall amounts are forecast to begin to decrease overnight Dec. 12-13. The NCHMF has also issued a level 1 warning of natural disaster risk due to heavy rainfall, tornadoes and lightning.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil. Disruptions to electricity and telecommunications services are possible where significant flooding, strong winds, or landslides impact utility networks.

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. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at airports in the affected regions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with 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 and some employees' inability to reach work sites.