New Zealand: Further adverse weather forecast over northern and northwestern parts of North Island through at least Feb. 2 /update 3

Event

Further severe weather, including heavy rainfall, thunderstorms, and strong winds, are forecast across northern and northwestern parts of North Island through at least Feb. 2. The heaviest rainfall is forecast across Northland, Auckland, and the Coromandel Peninsula Jan. 31-Feb. 1, with widespread rainfall totals of 8-17 cm (3-7 inches) expected across the affected area and isolated totals of up to 27 cm (11 inches) possible in parts of Northland. Heavy rainfall since Jan. 27 has caused widespread flooding and associated disruptions across much of the affected area, including Auckland. Further heavy downpours could trigger additional flooding and landslides, especially in areas where the ground is already saturated from previous rainfall.

As of late Jan. 30, the New Zealand National Meteorological Service (MetService) has issued the following weather warnings:

• Red Heavy Rain Warnings (the highest level on a three-tier scale): Northland; Auckland north of Orewa; and the Coromandel Peninsula.

• Orange Heavy Rain Warnings: Auckland from Orewa southwards and Great Barrier Island; and Bay of Plenty.

• Yellow Severe Thunderstorm Watch: Northland.

• Yellow Strong Wind Watch: Northland and Auckland.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Authorities in Auckland have declared a state of emergency after at least four fatalities following heavy rainfall late Jan. 27. Around 350 people require emergency accommodation, and at least 5,000 homes are being assessed for flood damage due to the widespread flooding in and around the city. Auckland Airport (AKL) closed late Jan. 27 due to flooding impacting the terminal building but has since begun to resume operations; however, significant flight disruptions are ongoing as operators work to clear the backlog, and passengers are advised to confirm flights before traveling to the airport. Further adverse weather over the coming days will likely have further impacts on flights. Schools in Auckland have been closed through Feb. 7, and beaches around the city are closed. The severe weather has impacted numerous roads across North Island; full details on road closures can be found here. Authorities in Auckland and other affected areas have advised residents to stay home and avoid traveling where possible due to the further severe weather forecast in the coming days.

Hazardous Conditions
Further 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 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. The disruptive weather may cause delays and cancellations at regional airports. 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
NZ Transport Agency