Civil Defence emergency operation centres have opened in Westport and Hokitika as the region prepares for a deluge of heavy rain that could bring slips and flooding.
MetService has issued a red warning, with up to 400mm of rain expected to accumulate in the ranges near Buller and up to 200mm near the coast between midday Wednesday and Friday evening.
Buller mayor Jamie Cleine said the escalation of the rain warning on Tuesday heightened the importance of the region being prepared and planning was well underway for what could be a significant event for the West Coast.
The heavy rain was due to coincide with high tides and there was concern for those in the north of the Buller district in places like Mohikinui, Seddonville and Karamea.
All the ingredients were there for the weather event to be similar to the deluge that caused widespread flooding last July, with almost half of Westport's residents evacuated from their homes, and at least 100 homes rendered unliveable by the floodwaters, Cleine said.
The 2021 flood event remained fresh in people's minds, he said.
"There's no doubt about it, that's a clear cause of additional anxiety as these sorts of events unfold, so we're very conscious of it.
"Our flood recovery hub was put on notice earlier this morning to expect increased inquiry and anxiety levels from the clients that they're working with."
It was important those in Buller monitored the official channels for further instructions over the next 24 hours - the West Coast Emergency Management Facebook page and on local radio stations, Cleine said.
"Start thinking about a getaway bag and what emergency supplies you might need and obviously think about where you might head if the call was to come to evacuate at some point."
MetService is predicting more than half a metre of rain near the mountains, inland Westland, from the early hours of Wednesday to Thursday evening, with thunderstorms continuing through the week. At the glaciers there could be 300mm of rain and up to 250mm on the coast.
Westland mayor Bruce Smith said he anticipated flooding, road outages and possibly worse.
The 2021 flood event in Westport remains fresh in residents' minds, Buller mayor Jamie Cleine says. Photo / RNZ
"We're just trying to get the message out to people to ensure that they fill their car up tonight - make sure it's full of petrol, ensure their standby plant has got fuel and that they've got basic groceries for two or three days, you know, it's basic Civil Defence stuff."
Warm winds and snowmelt combined with a massive rain event and dry ground conditions meant it had the potential to cause quite a problem on the coast, particularly around Fox and Franz Josef glaciers, Smith said.
"We've had such a dry spell, the ground is so dry, the waters just going to roar off it and head to the sea as quick as it can."
An emergency operations centre had been stood up at the council building in Hokitika and Smith said he hoped people would stay off the roads on Wednesday unless travel was absolutely essential.
"I think there's a high chance there's going to be a number of unexpected slips and we don't want people getting trapped in between slips or you know, getting caught in them unnecessarily."
The Department of Conservation (DOC) is closing the Paparoa Track tonight, after MetService issued a red warning for significant heavy rain on the West Coast.
DOC Greymouth operations manager David Deck said the difficult decision was made to close the entire 55km track from midnight February 1 until 8am on February 9.
"Due to the long spell of dry weather we've had, we expect some slips and windfall may occur and we'll need time to clear the track and ensure it's safe before it can be reopened."
All visitors with hut bookings would be contacted by the DOC booking team and offered a full refund.
Waka Kotahi Journey Manager Tresca Forrester said drivers were urged to be ready for extremely heavy rain from the early hours of Wednesday along the West Coast.
"People need to assess how urgent their trip is before heading out on the West Coast [on] Wednesday and Thursday.
"Roads will be affected and driving will be treacherous in such heavy downpours. People may face delays."
Westland was a difficult place to clear slips in a hurry, especially if there was ongoing rockfall or vegetation blocking the highway, Forrester said.
There are several places with no cell coverage in South Westland and people are encouraged to let their family and friends know if they are going to be travelling and what their expected timeline is.
