New Zealand: Severe weather forecast across western parts of South Island through at least early Oct. 25

Severe weather is forecast across western parts of South Island through at least early Oct. 25. A front will bring heavy rain as it moves over Fiordland Oct. 23 and then slowly northwards through Oct. 24. The heavy downpours will likely cause rising river levels and associated flooding in some low-lying areas, as well as landslides on unstable slopes. Hazardous travel conditions are likely due to slippery roads and debris from landslides.

As of early Sept. 25, the New Zealand National Meteorological Service (MetService) has issued the following weather warnings across the affected area:

• Orange Heavy Rain Warning (the middle level on a three-tier scale): Headwaters of the Otago Lakes and Rivers and Fiordland north of Doubtful Sound; 17.5-35 cm (7-14 inches) of rainfall are forecast in affected areas.

• Yellow Heavy Rain Watch: Westland District and the headwaters of the Canterbury Lakes and Rivers.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

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 rain saturates the soil. Disruptions to electricity and telecommunications services are possible where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows will likely render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Ponding on road surfaces would cause hazardous driving conditions on regional highways. Authorities will probably temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather will likely trigger intermittent flight delays and cancellations at regional airports, though these are unlikely to be severe or prolonged. Flooding will probably block regional rail lines; freight and passenger train delays and cancellations are likely in areas with heavy rainfall and potential track inundation. Localized business disruptions are probable in low-lying areas.