New Zealand: Further heavy rainfall is forecast in northeastern region through at least March 25 /update 3

Event

Further heavy rainfall is forecast over eastern North Island through at least March 25. Forecast models indicate that a slow-moving front will bring heavy rain to Hawke's Bay and Wairarapa through March 25. The heavy rain over Gisborne has eased, and authorities have since lifted the warnings; further rain is forecast and is likely to hamper recovery efforts.

A state of emergency remains in place across the Gisborne Region due to flooding. State Highway 2 remains closed from Ormond to Opotiki and Napier to Wairoa, State Highway 35 remains closed from Gisborne to Potaka and at the Gladstone Road Bridge, and State Highway 38 remains closed at Frasertown between Awamate Road and Pakowhai Road. Hundreds of people have been evacuated from Mangatuna, Makarika, Te Karaka, Uawa, Anaura Bay, Kaiaua, Tokomaru Bay, and Tolaga Bay. Emergency shelters are located at Manutuke School and Rangatira Scout and Community Hall. Approximately 240 customers remain without power in Ihungia, Makarika, Raupunga, Tapuaeroa, and Waingake. Authorities have requested residents to limit the use of water as all surface water in the districts is to be treated as contaminated.

As of March 24, the New Zealand National Meteorological Service (MetService) has issued the following warnings:

• Orange Heavy Rain Warning (the second-highest level on a three-tier scale): Hawke's Bay and Wairarapa; up to 16 cm (6 inches) of additional rainfall could occur in the area.

• Yellow Heavy Rain Watch: Gisborne south of Gisborne City.

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 additional 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. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. Multiple local roads in Gisbourne are closed due to flooding, landslides, and damage. More information about road closures in Gisbourne can be found here. The disruptive weather may cause flight disruptions at airports in the region, including Gisborne Airport (GIS).

Authorities may temporarily suspend port operations 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.

Resources

New Zealand National Meteorological Service
Waka Kotahi NZTA Central North Island Twitter
Gisborne District Council Facebook