West Coast mayors are urging their residents to be prepared and avoid travel amid red alert rain warnings - the most serious weather warning there is.
Westport flooding after red warning level rain in July 2021. Photo: Supplied/NZ Defence Force
Last July, after a similar red warning - almost half of Westport's residents were evacuated after major flooding inundated much of the town, causing millions of dollars in damage, and damaging hundreds of homes.
This year, dry summer soils, high tides, and forecast thunderstorm downpours were expected to exacerbate the danger.
MetService meteorologist Lewis Ferris told Morning Report the system would be very stationary over the next few days.
There would be a long period of heavy, persistent rain, he said.
"It looks like it could hang around as heavy persistent rain through to Saturday [in Westport] and that's much the same story as we move into Buller as well."
The West Coast would see a lot of washouts and potentially a lot of trees falling on hills, he said.
"The West Coast has been very dry in January and that rain really is going to create issues.
"Streams that are running extremely low or even just rivers that are running extremely low are going to rise very rapidly once those intense rainfall [downpours] do start to accumulate along those ranges."
Haast had recorded 80 millimetres of rain from about 8pm to 8am, which was almost twice as much as it had for the month of January, he said.
Buller District residents were being warned to pack an emergency getaway bag, make sure their cars were filled with petrol, and be prepared for evacuations at any time.
Buller District Mayor Jamie Cleine said they were planning for the worst.
"What we learnt from July was that some of our traditional evacuation centres are sort of less than ideal in a town flooding scenario so a lot of work going in yesterday out side of town, effectively up on the terraces which obviously presents some logistical problem around where people can shelter," Cleine told Morning Report.
Rural halls, sheds on farmland will be better than nothing and ready to go later today, he said. "They'll be high and dry."
Chorus were sandbagging roadsides in some places, and stormwater drains would be checked too, he said.
"Give consideration to property you could relatively simply move and organise the grab bags and begin monitoring local radio and Facebook.
"Also consider some of your friends and family that may be less able to act for themselves and make sure they've got a plan and are connected in with the information network as well."
"Organise the grab bags and begin monitoring local radio and Facebook" - Buller District Mayor Jamie Cleine
Westland District Council had begun preparing for flooding, and issued sandbags to residents and businesses in the lowest lying streets.
MetService forecasts up to 750 millimetres of rain could fall in the next few days about the Westland ranges, especially between Otira and Fox Glaciers, and massive amounts of rain were expected across the entire Westland and Buller districts.
Westport residents were being encouraged to collect sandbags to protect their properties.
People could collect sand and sandbags from the Kawatiri Coastal Trail - by the Buller Bridge and the Pulse Recreation Centre carpark - by the netball courts.
Buller District Council said it had as many bags as it could organise and asked people to only take what they needed to protect their property.
Westland mayor Bruce Smith says the rain began overnight, and high tide was expected just before 1pm.
"We've got a lot of snow that's melting and that's feeding the rivers, we've got obviously the front that's coming through but that significant part is we've the driest period of weather that we've had for many years and the ground is hard as hell.
"The rain is going to run off really quickly and that's going to create a big issue, potentially slips on roads and things like that."
Smith said people should make sure their car was full of fuel, they had two or three days of foods and stayed off the roads.
"The rain is going to run off really quickly and that's going to create a big issue" - Westland mayor Bruce Smith
Former Federated Farmers president Katie Milne is a dairy farmer at Lake Brunner, inland from Greymouth.
She told Morning Report with this kind of rain they were expecting water covering the grass for a couple of days and silting.
"We're prepared so that we won't have any stock losses and that's the main thing, making sure that everything gets through and then you can deal with the aftermath afterwards."
She had made sure all stock was on higher ground and away from a river that ran through the block.
The ground was hard as concrete making it difficult to put any temporary fencing in, she said.
She was hoping the rain didn't come in hard and fast.
"Sometimes it does come at such speed that we have some land washed away or culverts and drains get damaged, or little bridges get washed out. Fences certainly can get washed out or left covered in branches and stuff that comes down the rivers and damaged them that way".
'There can be a lot of cleanup of debris and old grass that washes through' - Katie Milne
Avoid non-essential travel - Waka Kotahi
Waka Kotahi was warning motorists across the South Island to avoid non-essential travel to the West Coast.
"If you have to travel, we're wanting you to take extra care but obviously if you can reassess your plans, that's what we are recommending in line with the Civil Defence advice as well," spokesperson Tresca Forrester told Morning Report.
Heavy rain had caused surface flooding on SH6 in South Westland.
Waka Kotahi said South Westland rivers were rising rapidly and there was surface flooding between Haast and Hokitika on low-lying areas of highway.
There was also surface flooding back into Otago, between Haast and Makarora.
Bridges would close if river levels were too high, Waka Kotahi maintenance contract manager Moira Whinham said.
State Highway 73 through Arthurs' Pass and SH6 through Haast Pass were expected to be the most affected.
"We're always just worried about slips and vegetation falling down on the road and obviously flooding, surface flooding on to the road."
Forrester said there were large sections of the coast which did not have cell phone reception.
Forrester said this could make it hard for people to get help if they needed it and difficult for Waka Kotahi to get crews in to clear roads.
Slips and flooding may make the roads impassible, especially at high altitudes, she said.
Crews had been deployed in remote areas, she said.
There was also an orange warning in Tasman people should be aware of, she said.
And with a strong wind watch in Canterbury, particularly in higher elevations and through SH7, people needed to be really aware of the wind gust when driving, she said.
Track closures
Several more West Coast tracks are closed due to weather conditions.
The Department of Conservation closed the Copland Track near Fox Glacier, as it was due to receive more than 100 millimetres of rain in 24 hours.
The Hokitika Gorge Walk, Pororari River Track and Bullock Creek Road tracks were all closed and DOC also closed its Lake Paringa and Ottos/MacDonalds campsites.
The Heaphy Track was closed until Saturday and the Paparoa Track was closed for a week.