04 Jan 2022 | 01:14 PM UTC
Tonga: Adverse weather forecast nationwide through at least Jan. 7
Severe weather forecast across Tonga through at least Jan. 7. Transport, business, and utility disruptions possible.
Event
A storm system will bring heavy rainfall, strong winds, rough seas, and possible flooding across Tonga through at least Jan. 7. As of late Jan. 4, Tonga Meteorological Services have issued gale warnings, heavy rainfall, flood, heavy damaging swell, extreme high tide, and small craft advisories for all regions. Officials could update and possibly extend the coverage of weather alerts over the coming days.
Winds of between 56-74 kph (35-46 mph), with gusts of up o 111 kph (69 mph), and sea swells of 4-6 meters (13-20 feet) are forecast across Tonga and flooding in low-lying coastal areas is possible due to high tides. There have been no initial reports of damage caused by the storm, although reports indicate minor flooding has occurred in Neiafu on the Vava'u Islands. Although the strong winds associated with the passing of the storm are forecast to reduce in intensity from late Jan. 5, further periods of heavy rainfall are likely across the country through Jan. 7.
Hazardous Conditions
The storm could produce rounds of heavy precipitation, strong winds, and isolated thunderstorm activity. 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 the soil has become saturated by heavy rainfall.
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. 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. Authorities may temporarily suspend port operations or close beach fronts if strong winds trigger hazardous sea conditions. 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.
Advice
Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and 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.
