This article is more than 7 months old

This article is more than 7 months old

Part of New Zealand’s South Island has become cut off after days of torrential rains washed away roads, forced the evacuation of 2,000 people and saw the country’s MetService issue its first ever red weather warning.

The flooding across the flat agricultural plains of Southland, in the island’s southernmost end, came a day after hikers and tourists were evacuated from another part of the region, Fiordland, where more than a metre of rain had fallen in less than three days.

Lewis Ferris at New Zealand’s MetService said the storms had generated its first red warning, a new alert the agency created in May last year. “The difference between the orange and red warnings is the impact on people,” he said. “We saw a road washed out, we saw people isolated. There was a real risk to communities given the impact on the roading network.”

In Southland, reports emerged of farmers trying to herd livestock to higher ground using a jetski or kayak. Neville Cook, a civil defence official, said: “There will be stock losses. Even with prior warning, there’s really nowhere they can go.”

In the township of Mataura, the floodwaters are inching closer to a paper mill where a chemical called ouvea premix is stored, which could release toxic ammonia gas if it comes into contact with water, authorities said. The gas – harmful to people and the environment – will likely be released into the floodwaters, though emergency management authorities hope it will be diluted by the water.

On Wednesday, police led evacuations across the region, including of the entire towns of Mataura and Wyndham, and much of the town of Gore. Those living on higher ground in Gore were allowed to stay, but should expect to be without power or water until Thursday, emergency management officials said.

Gore, which flooded after the Mataura river burst its banks, had been deluged by four times the amount of rain it would usually see at this time of year, said Ferris. More than 70mm of rain fell on Tuesday.

Emergency management officials in Southland, one of New Zealand’s largest and most sparsely populated regions, urged residents on social media to leave their homes as the waters continued to rise on Wednesday afternoon.

John Mckenzie (@Johnmck419) Mataura right now. Everyone currently being evacuated pic.twitter.com/I6wm2iQC5L

“Don’t be fooled by the blue skies, the impacts are significant and people shouldn’t be complacent,” said a post on the Emergency Management Southland Facebook page, referring to the sunny, clear weather in the region even as the swollen rivers burst their banks.

Between 200 and 300 people were staying in emergency centres in towns that were unaffected by the flooding, said Cook. Others were staying in hotels and motels in the region.

“People have been opening their businesses,” said Gary Tong, the Southland mayor. “It happens every time, it’s fantastic.”

But some in the area could face a long recovery.

Farmers had been given enough warning to move their stock to higher ground, Tong said, but added: “I understand some of those areas may be inundated.”

Jeremy Hughes - DTC 🚜🚜🚜 (@travelingfixer) Got sent these by a mate, his boss was moving a tractor between farms and had to do a wee rescue mission along the way. pic.twitter.com/gl7zU44qjW

A state of emergency was called for the region on Tuesday, after 100 hikers and about 70 people in vehicles were stranded by flooding and road closures in the picturesque tourist area of Fiordland. Eight helicopters flew over the bush trails to find and rescue those stuck.

Katie Todd (@Katietodd_NZ) Getting pretty touch and go in #Gore with 20 minutes until the Mataura River peaks @rnz_news pic.twitter.com/gAZT31jrjF

Nearly 200 tourists were also cut off in the township of Milford Sound when floods caused damage to the highway. Those people were being evacuated by helicopter on Wednesday, officials said.

• This article was amended on 11 February 2020. An earlier version misspelled the town of Wyndham as “Wynden”.