New Zealand: Further heavy rainfall forecast in northeastern areas through at least March 29 /update 4

Event

Further heavy rainfall is forecast over eastern portions of New Zealand's North Island through at least March 29. Disruptions have been reported in the Gisborne area following recent heavy rainfall, and the adverse weather is forecast to persist in the region over the coming days. Warning-level amounts of rainfall are notably forecast in Gisborne Region, particularly in the far south of the region, and in Wairoa District of Hawke's Bay through March 29. Further sustained rainfall could trigger additional flooding and landslides in affected areas, adding to the disruptions and hampering recovery efforts.

A state of local emergency remains in place across Gisborne Region due to flooding. State Highway 2 reopened March 25 after having been closed for two days; however, State Highway 38 remained closed between Wairoa and Frasertown, as well as State Highway 35 between Tolaga Bay and Potaka. 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. Authorities have requested that residents limit the use of water as all surface water in the districts is to be treated as contaminated. A boil-water notice is in effect for Waipukurau and is likely to remain in place until at least March 28. Power outages have been reported in some areas.

The Meteorological Service of New Zealand (MetService) had issued the following warnings as of early March 26:

• Heavy Rain Watch: Gisborne Region, south of Gisborne city; Wairoa District.

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 in affected areas.

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 Gisborne are closed due to flooding, landslides, and damage. To view more information about road closures in Gisborne, click 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 that experience heavy rainfall and track blockages. Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after weather 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

Meteorological Service of New Zealand (MetService)
Waka Kotahi NZTA Central North Island (Twitter)
Gisborne District Council (Facebook)