05 Mar 2021 | 05:17 PM UTC
Coral Sea: Severe Tropical Cyclone Niran continues tracking southeastward towards New Caledonia as of late March 5 /update 5
Severe TC Niran tracking southeastward in the Coral Sea towards New Caledonia as of late March 5. Close approach to New Caledonia March 6.
Event
Category-5 Severe Tropical Cyclone Niran continues to strengthen as it tracks southeastward in the Coral Sea towards New Caledonia late March 5. As of 2300 NCT, the center of circulation was approximately 815 km (506 miles) west-northwest of Noumea. Forecast models indicate the slow-moving system will weaken slightly as it tracks southeastward. The storm is forecast to make a close approach to New Caledonia by March 6, transiting off that country's southern coast before entering the South Pacific Ocean. Niran will begin to transition to a post-tropical cyclone by March 8; however, uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.
Government Advisories
As of 0119 NCT March 6, authorities in New Caledonia have placed the entire country on a level one tropical cyclone alert. Authorities will likely trigger a level-two tropical cyclone alert beginning 0600 NCT for the municipalities of Belep, Poum, Koumac, Kaala-Gomen, Voh, Kone, Pouembout, Poya, Bourail, Moindou, Farino, Sarramea, La Foa, Ouegoa, Pouebo, Hienghene, Touho, Poindimie, Ponerihouen, Houailou, Kouaoua, and Canala. The level-two alert will likely expand to the municipalities of Boulouparis, Paita, Dumbea, Noumea, Thio, Mont-Dore, Yate, Ouvea, Lifou, Mare, and Isle of Pines beginning 0800 NCT March 6. Officials will likely issue new warnings or update existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards. Localized evacuations could occur if weather conditions prove particularly hazardous.
Hazardous Conditions
Severe Tropical Cyclone Niran will probably bring heavy rainfall, strong winds, and rough seas to coastal areas of New Caledonia over the coming days. Sustained heavy rain could trigger flooding in low-lying communities near streams, creeks, and rivers, as well as in urban areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Rain-induced landslides cannot be discounted in steeply sloped terrains. Flooding could isolate some communities for several days.
Prolonged swells and storm surge generated by the system will likely result in coastal flooding, particularly as the system moves closer to land. Abnormally high tides are likely and could exacerbate storm surge throughout coastal New Caledonia. Persistent onshore flow could make it difficult for surge to recede and water levels to decrease in coastal river catchments.
In addition to the heavy rain, flooding, and storm surge, Severe Tropical Cyclone Niran will produce damaging wind gusts as it tracks near New Caledonia. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible.
Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least March 8. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports. Sea conditions and high winds could also disrupt handling and other operations at ports along the Queensland coastline. Disruptions caused by inclement weather and resultant hazards, such as flooding, could persist well after conditions improve. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions.
Advice
Activate contingency plans in areas where officials forecast tropical storm conditions. Heed all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents in waterproof containers. 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.
Plan accordingly for commercial, transport, and logistics disruptions in areas closest to the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or going to the airport; clearing passenger backlogs may take several days in some locations.
