MetService meteorologist John Law told RNZ Checkpoint the first impacts of the system could be felt on Saturday morning with large swells for north-eastern areas.

“This is a multi-hazard area of low pressure that runs down. You can imagine that these strong winds rushing over the seas help to drive large swells across the open waters, and they run in from the northwest.

Swells up to 6, 8 metres
“And I think around those northern coasts, places like Northland and the Bay of Plenty, swell heights could be as much as six to eight metres.

“Now, adding to that, the wet weather coming down the rivers, the strong winds, the extra boost of that sea by the extra low pressure, those coastal eliminations, that risk does increase.”

Law also said it was “very unusual” to see the entire North Island under weather watches and warnings.

“Normally our watches and warnings, we try and keep them to as small an area as possible to kind of really focus in on those areas impacting.

“So the fact that the whole island has got these severe weather watches and warnings … it is an indication of the severity of the system coming through, not just in terms of the wet weather, but that wind, I think, is going to be one of the key features as we head through the weekend.

“As this system runs across us, we’ll find our winds changing direction… as they come in to start with we’re looking at northerly winds, but as the system sweeps down to the south, strong south or westerly winds behind it will also be another issue.

“So that change in direction, something else to keep in mind.”

Orange heavy rain warnings
Meanwhile, Auckland, Great Barrier Island, Coromandel Peninsula, Bay of Plenty west of Whakatane including Rotorua, and Gisborne/Tairawhiti north of Tolaga Bay are all under an orange heavy rain warning from the early hours of Sunday morning.

Emergency Management and Recovery Minister Mark Mitchell says it will be a potentially significant and damaging storm, and Earth Sciences NZ predicted more than 200mm of rain could fall in some places across the upper North Island.

An orange strong wind warning is in place for Northland from 11pm Saturday until Sunday afternoon. Auckland, Waikato, Waitomo, Taupo, Taumarunui, Bay of Plenty and Rotorua, Gisborne/Tairawhiti, Hawke’s Bay, Taihape, Taranaki and Wanganui are all also under orange warnings which come into place overnight Saturday.

Aucklanders have been warned the Harbour Bridge might close due to strong winds.

FIFA matches advanced
FIFA World Cup qualifying matches due to be played in Hamilton on Sunday have been brought forward to Saturday to avoid the worst of it.

Officials said the decision was made to ensure the safety of participants and fans attending the games.

The Oceania semi-finals between the Football Ferns and Fiji and Papua New Guinea (PNG) and American Samoa were originally scheduled for Sunday afternoon in Hamilton.

They will now be played Saturday, with PNG playing American Samoa at midday and New Zealand playing Fiji at 4pm.

• RNZ is New Zealand’s statutory civil defence lifeline radio broadcaster. That means RNZ will provide vital information and updates as they come to hand on air and online during an emergency.
• Find the radio frequency for your area here and get prepared here.

This article is republished under a community partnership agreement with RNZ.

A tornado has torn through New Zealand’s Bay of Plenty settlement of Waihi Beach ripping roofs off houses and cutting power to nearly 1500 properties as post-Cyclone Gabrielle extreme weather continued to impact on the North Island.

Footage shows the storm tearing through the area about 9am on Saturday.

MetService said a severe thunderstorm watch for the Bay of Plenty had been lifted just before 10am on Saturday, but there was potential for further stormy weather.

• READ MORE: Cyclone Gabrielle: More heavy rain for NZ’s disaster-hit northern regions
• Follow RNZ updates
• Other NZ extreme weather reports

Meanwhile, more than 200 people spent the night sheltering in camps in Mangawhai in Northland on Friday night as several slips blocked exit routes, with the latest weather event still blowing through the North Island.

Overnight, Mangawhai residents who could not return home stayed over at schools in the Kaipara District.

MetService said the Mangawhai area received 300mm of rain over a seven-hour period.

Kaipara Civil Defence Controller John Burt said roads would be reassessed at first day light.

The majority of routes might remain closed due to major slips, including the main road between Kaiwaka and Mangawhai, he said.

Hawke’s Bay under heavy rain warning
MetService has put a heavy rain warning in place for Hawke’s Bay until 1pm on Saturday and a severe thunderstorm watch is in place until 5pm on Saturday.

Hawke’s Bay could expect a further 70-120mm of rain about the ranges, and also away from the ranges north of Hastings (which includes the Esk Valley area and the Wairoa District), MetService said.

Hawke’s Bay Emergency Management Controller Ian Macdonald said his biggest fear was if more rain than forecast fell.

Macdonald said localised downpours were a problem when silt was still around, but he believed the region was in a good position to cope.

“Plenty of resources at the moment, obviously we’re now fully activated and have been for a week and a half, we’ve got lots of NZ Defence Force here, so you know we’re in a good space if we do need to evacuate people.”

Police said the number of people who remained uncontactable in Hawke’s Bay and Tairāwhiti following Cyclone Gabrielle was 13 at 9pm on Friday — that is down from 56 people on Thursday evening.

The residents of Esk Valley were evacuated on Friday ahead of the heavy rain and Macdonald urged all Hawke’s Bay residents to be prepared to evacuate if they needed to.

Hawke’s Bay Civil Defence said a full assessment of Esk Valley would take place today.

It said the rainfall overnight was less than forecast, but MetService expects more rain across the region on Saturday.

Te Karaka residents advised to evacuate
Tairāwhiti Civil Defence Emergency Management on Saturday morning strongly recommended that people evacuate if they were in the Te Karaka township area.

The Waipaoa River at Te Karaka was expected to peak at 8 metres at 9am on Saturday.

In Gisborne, Mayor Rehette Stolz urged locals to seek help if they needed it this weekend, with the latest deluge likely causing more slips and flooding.

More atrocious weather had held back cyclone clean-up efforts and dampened people’s spirits, she said.

It may mean more people would need support from council and Civil Defence, Stolz said.

“We might have missed people and we want to know if you need anything, so if you need to make contact with the Gisborne District Council Civil Defence please reach out, we are there to help you.”

Tolaga Bay warning
Uawa Civil Defence in Tolaga Bay have urged people to stay off the roads as the Hikuwai river is currently at 11.5 metres.

The Hikuwai has begun to drop as rain has stopped in the area. State Highway 35 is closed from Okitu to Uawa due to flooding at Rototahi, SH2 at Ormond is also closed.

Meanwhile, staff from the National Emergency Management Agency and council are still working out how to make a risky debris dam safer, so locals can return home.

Sixty-four homes were evacuated in Tokomaru Bay on Thursday due to fears a debris dam on the Mangahauini River would fail during more heavy rain.

Stoltz said the dam had held up so far, and staff were working at pace to come up with a solution.

This article is republished under a community partnership agreement with RNZ.