04 May 2023 | 05:03 AM UTC
New Zealand: Adverse weather forecast over western North Island and northern South Island through at least May 6 /update 1
Severe weather forecast over parts of western and northern New Zealand through May 6. Flooding possible. Transport disruptions likely.
Event
Severe weather is forecast over western North Island and northern South Island through at least May 6. As of May 4, the Meteorological Service of New Zealand (MetService) has issued the following watches and warnings:
Orange Heavy Rain Warning (the middle level on a three-tier scale): Horowhenua to Wellington including the Tararua Range, Marlborough about and north of the Awatere Valley, Nelson, Northland, Taranaki north of Opunake to Whangamomona, Tasman, Tongariro National Park, and Waitomo. The heaviest rainfall of up to 45 cm (18 inches) is forecast over the ranges of Tasman.
Yellow Heavy Rain Watch: western parts of Auckland, Buller, Taihape except Tongariro National Park, Taumarunui, South Taranaki, Waikato, and northern Whanganui.
Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days. Authorities have warned that there is a possibility that some of the orange warnings for Marlborough, Nelson, Taranaki, and Tasman may be upgraded to Red Heavy Rain Warnings later May 4.
State Highway 1 between Kitchen Road and Makene Road through the Mangamuka Gorge is closed due to multiple landslides and damage. State Highway 2 is closed in the Waimana Gorge between Station Road inTaneatua and Wainui Road in Kutarere due to flooding and landslides. The highway remains closed between Eskdale and Tutira and at the Waikare Bridge due to damage caused by Cyclone Gabrielle. State Highway 25A between Kopu and Hikuai is closed due to a full road collapse at a large washout location. Traffic restrictions are in place on State Highway 31 from Kawhia to Tihiroa due to a landslide.
Authorities in Auckland have canceled ferry services across the Gulf Harbour May 4 as a precaution. The Whakatane District Council reported power outages in Awakeri, Coastlands, and Poroporo due to a landslide late May 2, affecting more than 670 people. Landslides May 3 cut off the townships of Taneatua and Ruatoki. one property in Taranaki has been evacuated due to flooding. Further evacuations are possible due to the ongoing severe weather.
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. Additional power outages are possible in areas impacted by the weather system.
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 additional delays and cancellations at airports across the affected region. Flooding could block regional rail lines; freight cancellations are possible in areas subject to 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 or reported. Do not drive on flooded roads. Charge battery-powered devices in the case of prolonged electricity outages.
