New Zealand: Severe weather forecast to continue across parts of South Island and southern North Island through at least Aug. 25 /update 1

Severe weather is forecast to continue across parts of western and northern South Island and southern North Island through at least Aug. 25. A front is forecast to track eastward over South Island Aug. 23 and North Island Aug. 24, bringing heavy rain to the western areas, and possible severe northwest gales for Wellington and inland Canterbury. Another front is forecast to bring heavy rain to Fiordland late Aug. 24-25.

As of early Aug. 23, 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): Buller District, headwaters of the Canterbury lakes and rivers about and south of Arthur's Pass, Mt Taranaki/Taranaki Mounga, Tararua Range, Tasman northwest of Motueka, and Westland District; rainfall over up to 10 cm (4 inches) is forecast.

• Yellow Heavy Rain Watch: Fiordland about and north of Doubtful Sound, Grey District, and Richmond and Bryant ranges, including the Rai Valley.

• Yellow Strong Wind Watch: Canterbury High Country and Wellington.

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 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 or landslides impact utility networks.

Floodwaters and debris flows will likely render some bridges or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces will probably cause hazardous driving conditions on regional highways. Authorities will likely temporarily close some low-lying routes that become inundated by floodwaters. Flight delays and cancellations at airports are probable.

Localized business disruptions are likely in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.