11 Jul 2022 | 11:26 AM UTC
New Zealand: Adverse weather forecast across much of the country through at least July 13
Heavy rainfall, snow, and strong winds forecast much of New Zealand through at least July 13. Flooding and transport disruptions possible.
Event
A weather front passing over New Zealand is expected to bring heavy rainfall, snowfall, and strong winds across many parts of the country through at least July 13. The weather front has arrived in the north of the country late July 11 and will spread southwards over most of the country through July 12. Some areas will receive rainfall totals of around 15 cm (6 inches) and winds gusting up to 110 kph (68 mph) are possible in Auckland early July 12. Auckland's transport authority has warned that the strong winds could force the closure of the Harbour Bridge and have warned of delays to bus and ferry services.
As of July 11, the New Zealand National Meteorological Service (MetService) has issued the following warnings and watches:
Orange Heavy Rain Warning (the middle level on a three-tier scale): Coromandel Peninsula; Bay of Plenty including Rotorua; Gisborne north of Tolaga Bay; Taupo and Taihape; North Taranaki including the mountain; Tasman; the Tararua Range; Marlborough including Kaikoura Coast; Canterbury excluding Christchurch and Banks Peninsula; and North Otago and Dunedin.
Orange Heavy Snowfall Warning: Canterbury High Country south of Waimakariri River including Mackenzie Basin.
Orange Strong Wind Warning: Auckland and Great Barrier Island; Tasman west of Motueka; Buller; and Westland about and north of Fox Glacier.
Orange Heavy Swell Warning: Kapiti-Porirua Coast - Otaki to Cape Terawhiti; and Wairarapa - Turakirae Head to Cape Palliser.
Yellow Heavy Rain Watch: Gisborne about and south of Tolaga Bay; Hawke's Bay; the Tararua District and Wairarapa excluding the Tararua Range; Christchurch including Banks Peninsula; Coastal Clutha; Northland; Auckland and Great Barrier Island; and Waikato excluding Coromandel Peninsula.
Yellow Heavy Snowfall Warning: Canterbury High Country about and north of Waimakariri River; and North Otago, Central Otago, and the Queenstown Lakes.
Yellow Strong Wind Watch: Northland; Coromandel Peninsula, Waikato, Waitomo, Taumarunui, and Taranaki; Bay of Plenty, Rotorua, Taupo, and Taihape; Whanganui, Manawatu, Kapiti-Horowhenua, Wellington, and Marlborough Sounds; Hawke's Bay south of Hasting, Wairarapa including the Tararua District; Tasman about and east of Motueka; Westland south of Fox Glacier; and Christchurch including Banks Peninsula.
Road Snowfall Warning: Dunedin to Waitati Highway (SH1), Lewis Pass (SH7), Lindis Pass (SH8), Arthur's Pass (SH73), Porters Pass (SH73), Milford Road (SH94), and Crown Range Road.
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 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. Authorities may temporarily suspend port operations along the Tasman Sea 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.
