28 May 2021 | 04:07 AM UTC
New Zealand: Heavy rainfall forecast in parts of central regions through at least early May 31
Heavy rainfall forecast in parts of central New Zealand through May 31. Flooding and transport disruptions possible.
Event
A low-pressure system is bringing heavy rainfall to central New Zealand as of May 28. The Meteorological Service of New Zealand (MetService) has forecast heavy rainfall and strong winds through early May 31.
As of May 28, authorities have issued the following warnings:
Red-level heavy rain warning (the highest alert level on a four-tier scale) for Canterbury.
Orange-level heavy rain warning for Nelson.
Yellow-level heavy rain watches for the rest of the affected area, including Bay Of Plenty, Taranaki, the Richmond Range including the Rai Valley, and Marlborough.
Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change.
Hazardous Conditions
Periods of heavy rainfall could trigger flash 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. Strong winds could down trees or powerlines, causing power outages.
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 regional airports. Authorities may temporarily suspend port operations along the Tasman Sea, South Pacific Ocean, and Bay of Plenty 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.
