New Zealand: Heavy rainfall and strong winds forecast in northern and far southwestern regions through at least April 13

Event

Heavy rainfall and strong winds are forecast in North Island and far southwestern regions in South Island through at least April 13. The remnants of Tropical Cyclone Fili is forecast to approach New Zealand from the northwest, bringing widespread impacts to North Island, including heavy rain and severe gales. Very large waves are likely along the northeastern and eastern coasts of North Island. A separate front is forecast to bring rain to the west coast of South Island April 11-12. As of April 11, the New Zealand National Meteorological Service (MetService) has issued the following warnings:

• Heavy Rain Warning (second-highest level on a three-tier scale): Bay of Plenty, Coromandel Peninsula, Gisborne, Hawke's Bay, Fiordland, Northland, and Rotorua; up to 20 cm (8 inches) of rainfall could occur, especially in Hawke's Bay.

• Strong Wind Warning: Auckland, Coromandel Peninsula, Gisborne, and Great Barrier Island; gusts of up to 140 kph (87 mph) are possible, especially around Great Barrier Island.

• Heavy Rain Watch: Auckland including Great Barrier Island and Westland south of Ross.

• Strong Wind Watch: Bay of Plenty, Hawke's Bay, Horowhenua Kapiti Coast, Manawatu, Northland, Rotorua, Taihape, Tararua District, Taumarunui, Taupo, Taranaki, Waikato, Wairarapa, Waitomo, Wellington, and Whanganui.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days. The heavy rain is likely to lead to rapid water level rises in rivers and streams. Surface flooding, landslides, and hazardous driving conditions are possible.

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. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. The disruptive weather may cause some delays and cancellations at airports in the region, including but not limited to Auckland International Airport (AKL) and Wellington International Airport (WLG). Authorities may temporarily suspend port operations along the Tasman Sea and Cook Strait 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 that see 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