14 Dec 2021 | 06:49 AM UTC
New Zealand: Heavy rainfall forecast in northern and eastern regions through at least Dec. 16 /update 1
Heavy rainfall forecast in northern and eastern New Zealand through at least Dec. 16. Flooding, disruptions ongoing.
Event
Heavy rainfall is forecast in northern and far southern North Island as well as far northwestern and northeastern South Island through at least Dec. 16. The affected areas include portions of Auckland, Bay of Plenty, northeastern Canterbury, northern Gisborne, far northern and far southern Manawatu-Wanganui, eastern Marlborough, Nelson, Northland, northwestern Tasman, eastern Waikato, and western Wellington regions. As of Dec. 14, the New Zealand National Meteorological Service (MetService) has issued the following warnings:
Heavy Rain Warning (the middle level on a three-tier scale): Bay of Plenty, Coromandel Peninsula, Gisborne from Tokomaru Bay northwards, Tasman about and west of Motueka, Tararua Range, eastern Marlborough, and Canterbury Plains north of Ashburton including the foothills and Christchurch; up to 22 cm (8.5 inches) of rainfall could occur in the area, especially in the Bay of Plenty.
Heavy Rain Watch: eastern Waikato, Taupo, Wellington, Kapiti, Horowhenua, northern and eastern Northland, and eastern Auckland including Auckland City and Great Barrier Island.
Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.
Hazardous Conditions
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 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. Power outages could occur throughout the affected area.
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. Raetihi Pipipriki Road connecting the Whanganui River settlement of Pipiriki with the Ruapehu District is closed due to a landslide. Several urban and rural roads are also closed in Paraparaumu on the Kapiti Coast. Reports indicate traffic disruptions on State Highway 1 on Mana Esplanade in Wellington due to overflowing wastewater manholes and between Manakau and Ohau River bridge, south of Levin in Manawatu, due to flooding. State Highway 2 near Te Awe Awe Road in Eketahuna and State Highway 54 near Vinegar Hill, Manawatu-Wanganui, are also experiencing disruptions due to flooding. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. The disruptive weather may cause flight disruptions at regional airports. Reports indicate delays and cancellations impacting at least 113 regional flights at Wellington International Airport (WLG) due to a faulty airport landing instrument Dec. 14. Authorities are waiting for the weather to clear before they fix the system. Larger airplanes are operating normally, as they can land without the instrument.
Authorities may temporarily suspend port operations along the Bay of Plenty, South Pacific Ocean, and Tasma Sea if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight cancellations are possible in areas with heavy rainfall and potential track blockages. Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.
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.
