Tonga: Adverse weather forecast across much of the country through at least Oct. 19

Severe weather is forecast across much of Tonga through at least Oct. 19. A slow-moving weather trough will bring heavy rainfall and thunderstorms across most of the country over the coming days. Strong winds may accompany storms and rough seas are likely in coastal areas. As of late Oct. 16, Tonga Meteorological Services have issued heavy rainfall, flash flood, and gale warnings and small craft and extremely high tide advisories for Tongatapu and 'Eua. Heavy rainfall, flash flood, and extremely high tide advisories are in place for 'Otu Mu'omu'a and Ha'apai. Extremely high tide advisories are in place for the rest of Tonga and gale warnings have been issued for Telekitonga and Telekitokelau. Officials could update and possibly extend the coverage of weather alerts over the coming days.

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 stormwater drainage systems. Sites located 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 rainfall has saturated the soil.

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.

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 regional airports. If strong winds trigger hazardous sea conditions, authorities may temporarily suspend port operations or close beach fronts. 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.