File photo. Photo: RNZ / MARIKA KHABAZI
People around the country are being warned to prepare for widespread heavy rain - and there was an increased risk of flooding and landslides.
National Emergency Management Agency director John Price said the organisation was working with Civil Defence to ensure they had the resources they needed before bad weather arrived.
Warning for Bay of Plenty
MetService on Tuesday morning, shortly before 10am, issued an orange heavy rain warning for Bay of Plenty, including Rotorua.
The forecaster said it was expected, with other parts of the upper North Island - such as Coromandel, Northland and Auckland - already under warnings.
"MetService is predicting heavy rain with possible thunderstorms and 80 to 100 mm accumulating," between 3pm and 3am Wednesday, it said.
Heavy rain warning and a severe thunderstorm watch for Auckland
MetService has issued an orange heavy rain warning and a severe thunderstorm watch for Auckland, including Great Barrier Island, for all of Tuesday.
The region could see localised torrential rain of around 50mm to 70mm, and an active front could bring thunderstorms on Tuesday afternoon and evening.
MetService communications meteorologist John Law told Morning Report on Tuesday there was a "distinct possibility" of flooding.
"The ground is already very saturated from that rainfall we've had over the last few days, and I think it's worth saying, although we've got this period of rain, it's also going to be that intensity … those thunderstorms which can bring a lot of rain in a very short space of time, so it's definitely worth keeping up to date with the thunderstorm watches and warnings.
"The watches are there because we think the conditions exist for thunderstorms to form, and a warning will be issued if we can detect one of those thunderstorms on our radar networks - so really worth keeping up to date with those. It could be really intense."
"It could be really intense" - MetService communications meteorologist John Law
Auckland Emergency Management (AEM) duty controller Parul Sood said Aucklanders should remain vigilant and have an emergency plan in place if they needed to evacuate, especially those people who live in isolated areas, or areas prone to flooding.
People should check the Auckland Emergency Management website and social media channels to see whether civil defence centres had been activated, she said.
AEM head of engineering resilience Ross Roberts said properties next to, above or below properties affected by existing landslides may be at increased risk of further landslides.
Chance of tornado in Northland
People in Northland are also being told to brace for thunderstorms.
MetService has issued orange heavy rain warnings for Coromandel and Northland.
The active front is expected to hit on Tuesday bringing with it torrential rain of 40mm an hour and a slight chance of a tornado.
Driving conditions will also be hazardous, with the potential of flooding and low visibility.
"Looks like we've got some clearer weather heading our way later on this week, but for now it is definitely very wet," Far North Mayor Moko Tepania told Morning Report. "A little bit extra hard right now."
He was most concerned about what would happen when high tide hit - about 10am on the western coast, and midday for the east.
"Whenever we get any intense downpours of rain with a high tide, it does seem to affect our road corridors on the coastal communities … so we'll be watching for that today."
"For now it is definitely very wet" - Far North mayor Moko Tepania
A number of existing slips from past weather events may have been exacerbated, he warned, but current catchment systems were holding up well.
West Coast
MetService has issued an orange weather warning for Westland, with 150mm of rain expected near the coast and up to 350mm in the ranges.
Westland District Council made pallets of sandbags available before the forecast heavy rain.
The council said sandbags were available on four streets in central Hokitika, for those in areas likely to be worst-affected by flooding.
- Corner of Stafford and Sewell Streets
- Corner of Hamilton and Tancred Streets
- Corner of Tancred and Weld Streets
- Corner of Weld and Sewell Streets
West Coast Emergency Management group manager Claire Brown told Morning Report that so far, there had been "very minimal take-up".
Residents were also urged to be mindful on the roads and drive slowly through flood waters or avoid the affected areas altogether.
A lot more rain on the way over the next few days for northern and western areas. Photo: MetService
MetService has issued an orange weather warning for the Grey and Westland districts, with up to 240mm of rain about the ranges and up to 150mm nearer the cast through to 9pm on Tuesday.
West Coast emergency staff were on standby around the region should bad weather escalate overnight.
Brown said there had been no major impacts overnight, with variable amounts of rain falling in different places - between 10mm and 70mm.
Only one river caused any kind of alarm - the Waiho River at Franz Josef.
"Other than that, everything seems to be pretty good so far. Obviously it's still quite early," Brown said.
"Everything looks like it's going pretty good so far … so far, so good."
"So far, so good" - West Coast Emergency Management spokesperson Claire Brown
But with the heaviest falls expected Tuesday morning, they were "keeping a close eye" on the situation.
"We are continuing to track as expected. There's probably a few more hundred [millimetres] to fall during the course of the day, but again, it has been quite variable."
South Island
MetService had a heavy rain warning in place for Tasman from Motueka westwards from 6am, with 85mm of rain falling in the Tasman ranges since midnight and about another 100mm expected on top of that.
"That heavy rainfall can cause rivers to rise rather rapidly," Civil Defence Nelson-Tasman spokesperson Paul Shattock said.
"There will be lots of surface water on the roads, so people really need to take care out there."
"We always recommend people be prepared" - Civil Defence Nelson-Tasman spokesperson Paul Shattock
This latest rain comes after a wet few months, raising the risk of slips. Shattock said the local Nelson and Tasman councils had staff at key locations, keeping an eye on things.
"We also have a team of geotechnical engineers on standby who will be monitoring slips as well, that occurred in the August 2022 event."
Maitai River levels were expected to rise, but not break its banks.
"We always recommend people be prepared, and if they have in the past needed sandbags to redirect water, then we strongly encourage them to have it on hand," said Shattock. "At this stage though, hydrologists are expecting for it to be around about an annual to one-in-five-year flood on the Maitai, which isn't overtopping banks or anything like that. Fingers crossed that's where it heads."
The weekend's rain already had some roads closed, with more details on the councils' websites, he said.
Cold to follow rain
Law said this week's rain would be followed by a couple of dry days, then a wintry cold snap.
"The good news is as we go through towards say the middle part of this week, we should find some drier weather there. But I think we are just going find it just takes its time to clear off today…
"As we go through towards the end of this week, we find the winds change direction, cold air stretches across New Zealand," he explained.
"Temperatures on Thursday probably cooler than our minimums last night ... and we have got some snow - there's a road snow warning out already for the Crown Range Road tonight, Tuesday and towards Wednesday, and we could well find some more snow about those higher parts of the South Island of about 400 or 500 metres, and even across the top of Mt Tongariro, as we go into Thursday.
"It's a real change - it's very, very different to what we've been having over the last few weeks."