A state of emergency has been declared in Buller and people are being forced to evacuate after a deluge of rain on the already soaked West Coast.
Some houses have had water through them as Westport experiences its wettest February in 78 years.
The heavy rain overnight arrived as the trough weather system was set to move northwards across the South Island before weakening over central New Zealand today, MetService said.
At 6pm, Controller Sean Judd said additional streets need to evacuate immediately as rainfall is set to peak in the coming hours.
"We expect it to peak in the next few hours. We do not anticipate this to be a significant issue – we are constantly monitoring the levels. However, as a result of this additional information, we have decided to add to the mandatory evacuation order."
As of 9pm there are 103 people in Westport Evacuation centres, while only eight people have been forced to evacuate in Waimangaroa.
A West Coast Emergency Management spokesperson said the number of houses forced to evacuate will be available tomorrow.
Just before 9pm, Buller Emergency Management said they are monitoring the river levels.
"There is a little time left before we are out of the woods with the river potentially peaking at 10pm. Currently river levels in Westport are dropping."
Meanwhile, Fire and Emergency NZ at the Westport hospital pumping water out of the basement.
People who live on these additional streets need to evacuate immediately:
• Domett St between Larsen and Mill Sts
• Colvin St
• Riley Place
• Gothard Place
• Scanlon Place
• Rintoul St between Derby and Colvin Sts
• Fonblanque St between Derby and Colvin St
Earlier this afternoon a spokesperson for West Coast Emergency Management said evacuations are now mandatory.
BIG thank you to all of our evacuation centres who have set up for our evacuated residents. Here are some pictures...
Posted by Buller Emergency Management on Wednesday, February 9, 2022
"The modelling suggests that low laying areas of Westport are at serious risk of flooding and we must put people's safety first. We put a mandatory evacuation order in place for these at-risk areas in Westport to ensure residents' safety.
"If your house is within the evacuation zone you must go to higher ground and seek alternative accommodation such as staying with family or friends outside of the evacuation zones."
If residents cannot stay with family or friends, evacuation centres are open at South School and Carter's Beach Top 10.
Buller Emergency Management controller Bob Dickson gave an update at 4.30pm via a live video post.
"It's been a very, very challenging day for everyone in the Buller district," he said.
"We've had rivers flooded, we've had roads closed, we've had some houses with water through them, we've had mandatory and voluntary evacuations under way, and I've got to say that people have responded magnificently."
Although there has been "tremendous support" from police, Fenz, and other agencies including LandSar, it's been a tiring effort, Dickson said, and a night-shift team takes over soon.
But the weather is looking calmer, he said, despite the odd heavy shower coming through.
The Buller River is also still very high at around 11.4m but they are expecting to see it start to recede.
"But there is no place now for complacency," he urged.
The coast road is open although both gorges are closed, and won't be assessed until later tomorrow morning. There are also reports of surface flooding and slips.
"So, there's still some significant challenges ahead of us," Dickson said.
He acknowledged evacuations are stressful and difficult for residents but "unfortunately that is the new reality we are living in and adaptation is the key".
"Be prepared. There is more change ahead of us, potentially over the coming weekend.
"You must take steps to look after yourself, your neighbours, your friends and pets."
An evacuation centre has been set up at Sergeants Hill Hall, South School Hall, Waimangaro Hall and Carters Beach Motor Camp.
Residents are urged to follow the evacuation order to keep safe, they said.
Niwa has advised the Buller River is running to 11.4m at Te Kuha.
Modelling shows the situation will be similar to the July 2012 floods.
They say the rising tide may coincide with any push of the river, which could make the situation more serious.
A spokesperson for Buller District Council said the rain was under-forecast in terms of intensity and impacts and it has isolated the district.
The Buller Emergency Operations Centre (EOC) has been stood up again.
"The Emergency Response is in hand, and the Emergency Operations Centre is here to help those who cannot help themselves," Dickson said earlier.
"Due to our current isolation, we don't currently have the additional resource present in the district."
Buller mayor Jamie Cleine said significant rain was expected to continue until midday or so in the area.
"There are a lot of difficulties getting around the district because of road closures.
"The river at the moment is absolutely raging, way higher than it was last week, up to about 11 metres and rising," he said.
West Coast DHB staff were preparing to evacuate Buller Health and will provide further updates as details are confirmed.
Buller Medical remains open for urgent care. If you live north of Westport, staff are in Karamea and Ngakawau. And if you are in Reefton, Reefton Health is open.
Heavy rainfall has affected most of the district, with surface flooding and slips on all access routes into Westport.
Road closures are affecting all key state highways with contractors working to establish access, the council spokesperson said.
A number of highways on the West Coast and one in Tasman have been closed because of surface flooding and slips.
• SH6 Inangahua to Westport
• SH6 8 Mile to Inangahua
• SH6, SH65 Murchison to Springs Junction
• SH7 Springs Junction to Reefton
• SH67 Westport to Mokihinui
• SH67 Mokihiniu to Karamea
• SH69 Inangahua to Reefton
People travelling between Christchurch and Nelson will need to detour via Blenheim.
Multiple sections of State Highway 6 have been reduced to a single lane between Blenheim and Nelson from storm damage over the weekend.
And the Department of Conservation has announced the partial closure of the Heaphy Track after last week's rain is expected to last for several months.
Three bridges have been extensively damaged or destroyed between the Heaphy Hut and James Mackay Hut.
"We know that this is extremely disappointing for many trampers and mountain bikers who had plans to do the Heaphy Track in coming months," says DoC's Buller operations manager Suvi Van Smit.
"However, with the Heaphy River, Gunner River and Pitt Creek bridges all out of action, there is no safe way to get from Heaphy Hut to James Mackay Hut. We have had to make this decision to extend the closure with our customers' safety in mind."
However, there is little or no track damage between Brown Hut and James Mackay Hut.
"From February 13 it will be possible to do a return walk from the Golden Bay end of the track (Brown Hut) as far as James Mackay Hut allowing walkers to stay at the huts and campsites within this section, by booking a two, three or four-day return trip."
Fire crews were also kept busy overnight.
Southern fire communications shift manager Jill Higgison said they were called to properties in Westport, Reefton, Waimangaroa and Granity.
Firefighters were needed to pump water out of the homes, she said.
Despite the callouts, no injuries were reported at any of the homes, Higgison said.
Oppressive humidity will persist for the coming days.
— NIWA Weather (@NiwaWeather) February 9, 2022
Note the connection to a tropical low near New Caledonia. This will support heavy rain over the coming days for parts of the motu.
Impacts such as slips and flooding are distinctly possible. pic.twitter.com/aHzNc9MJTI
A slip in Waimangaroa, just north of Westport, has also sparked the evacuation of multiple homes in the area overnight.
Fire and Emergency NZ said the move was a precautionary evacuation because of the accumulation of rain from the past week.
Much of the South Island is set to plunge below 0C tonight and tomorrow.