20 Jan 2021 | 04:59 AM UTC
New Zealand: Heavy rainfall, strong winds forecast in southern and western South Island through early Jan. 21
Severe weather to continue in southern and western South Island, New Zealand, through early Jan. 21. Transport disruptions possible.
Event
Severe weather is forecast to continue in South Island's southern and western regions through at least early morning Jan 21. Meteorologists predict heavy rainfall and strong wind gusts will continue in Coastal Southland, the Westland ranges, and Fiordland. The New Zealand National Meteorological Service has issued a heavy rainfall warning for mountain ranges in Westland south of Otira and Fiordland; authorities project 8-9 cm (3-3.5 inches) of rainfall could occur in these areas. A Heavy Rain Watch in effect for mountain ranges in Westland north of Otira, Buller, and Coastal Southland. A Strong Wind Watch is in effect for parts of Fiordland, though strong gusts are possible throughout the affected area. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.
Hazardous Conditions
The storms could produce rounds of heavy rainfall, strong winds, and isolated thunderstorm activity. Sustained heavy rain 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 in areas where strong winds are forecast.
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 in the Foveaux Strait if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight train delays and 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 in the affected area. 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.
