21 Jul 2023 | 01:26 AM UTC
New Zealand: Heavy rainfall and strong winds forecast across North Island and northern and central South Island through at least July 23 /update 1
Heavy rainfall and strong winds forecast in northern and central New Zealand through July 23. Disruptions likely.
Event
Heavy rainfall and strong winds are forecast across most of North Island and northern and central South Island through at least July 23. The New Zealand National Meteorological Service (MetService) warned that a low-pressure system over northern New Zealand is likely to remain slow moving July 21 before slowly tracking south to southeast through July 23, bringing heavy rain and strong winds to many parts of New Zealand. As of July 21, the MetService has issued the following weather warnings:
Orange (middle level on a three-tier scale) Heavy Rain Warning: Coromandel Peninsula and Tairawhiti/Gisborne. Further 13 cm (5 inches) of rain is forecast.
Yellow Heavy Rain Watch: Auckland, Great Barrier Island, Canterbury, ranges of Hawke's Bay, eastern Marlborough south of Ward, and Wairoa District.
Yellow Strong Wind Watch: Auckland, Bay of Plenty southeast of Whakatane, Buller, Coromandel Peninsula, Great Barrier Island, Horowhenua, Kapiti, Manawatu, Marlborough, Nelson/Tasman, Northland, Taihape, Taranaki, Taumarunui, Taupo, Waikato about and just west of the Kaimai Range, Waitomo, Westland north of Hokitika, and Whanganui.
Road Snowfall Warning: Lewis Pass (SH7), Arthur's Pass (SH73), and Porters Pass (SH73).
Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.
Reports indicate that several neighborhoods in West Auckland are flooded. Around 5,000 properties in Coromandel, more than 5,000 other properties in Whitianga and Hikuaiare, and more than 600 people in Kapiti and Manawatu districts are without power. One of the major wastewater pump stations to the south side of Whitianga has failed. The Mercury Bay Area School in Whitiangi is closed July 21.
State Highway 1 between Kitchen Road and Makene Road through the Mangamuka Gorge, State Highway 25 between Te Kouma Road and Marae Road as well as around the intersection with Wade Road and near the intersection of Otuturu Crescent by Ruamahunga, State Highway 25A between Kopu and Hikuai, and State Highway 50 between Tikokino Road and Bridge Street intersection, are closed due to flooding, landslides, and damage.
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 stormwater drainage systems. Sites 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 heavy rainfall has saturated the soil.
Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are likely where significant flooding, landslides, or strong winds impact utility networks.
Transport
Floodwaters and debris flows will likely 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 cancelations at airports in the affected regions. Flooding could block regional rail lines; freight cancellations are possible in areas with heavy rainfall and potential track blockages.
Localized business disruptions will likely occur in areas impacted by severe weather; some businesses might not operate at full capacity because of damage to facilities, possible evacuations, and some employees' inability to reach work sites.
Advice
Monitor local media for weather-related updates and advisories. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible delivery delays throughout the affected area. Allow extra time to reach destinations and carry an emergency kit and warm clothes if driving is necessary, especially on secondary or rural routes that could become impassable. Charge battery-powered devices in the case of prolonged electricity outages.
