Video and images from Friday and Saturday show the extent of the damage caused by flooding after a severe weather event in Auckland.
After “unprecedented” rain in Auckland on Friday and Saturday, the MetService is warning North Islanders to brace for more heavy rain on Sunday.
Heavy rain watches are in place for Auckland, Great Barrier Island, Taupō and Hawke’s Bay south of Wairoa.
A severe thunderstorm watch is also in place for the Coromandel Peninsula, Bay of Plenty, Rotorua and Taupō. The warning will remain in place from 9.30pm on Saturday through to 9.00am on Sunday.
Throughout Auckland and Great Barrier Island, showers are likely throughout Sunday, with heavy periods of rain possible into Monday. Thunderstorms are also possible.
The slow moving low behind the storm is expected to hang about just west of the upper North Island until Tuesday when it moves east into the Tasman Sea.
Localised downpours of between 25mm-40mm of rain per hour are expected over western and central parts of the North Island and Bay of Plenty and eastern Taupō on Saturday, MetService meteorologist Dan Corrigan said.
“That’s very heavy rain to be falling in a short time.”
Rainfall of this intensity can cause surface and flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.
Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.
For context, the flooding inside Auckland Airport’s international terminal on Friday night occurred after 71mm of rain fell in one hour as the storm stagnated over the city.
“When we normally talk about heavy rain, we're looking at rainfall intensities of six millimetres an hour or more. The rain was 10 times intense there than what we would normally start calling heavy.”
There is a MetService ran watch in place for more rain on Sunday from 6am until midnight.
“The main rain band has moved off to the east of Auckland for the time being and there are a number of Orange Warnings and Watches in place around the North Island.
“The main rain band returns to Auckland and Northland later on Sunday but rain will come and go for many areas in the North Island,” MetService meteorologist Angus Hines said.
While the expected rain should not match the intensity of Friday, impacts are expected to be severe and wide-reaching.
More flooding will occur through many northern regions in the coming days, and people should stay abreast of the latest information from local emergency management, Civil Defence and MetService.
In Bay of Plenty and Gisborne, north of Ruatoria and Coromandel, intense downpours will be over smaller areas – towns instead of regions.
Bay of Plenty police are warning motorists to stay off the roads unless travel is essential.
Heavy rain has caused multiple slips, brought down several large trees, police said in a statement.
Roads are blocked and there is already widespread flooding, expected to worsen over the course of the day, police said.
SH2 is closed at Maniatutu with diversions in place, while a landslide is partially blocking SH29 at Omanawa.
People in all affected regions should keep up to date with forecasts and rain radars as the storm developed, Corrigan said.
A heavy rain warning is also in place for Wairarapa including the Tararua District where 70mm to 100mm of rain is expected about the ranges, with localised downpours of 25-40mm of rain from Saturday afternoon.
Another period of heavy rain is possible for Auckland on Sunday, with more thunderstorms possible during the afternoon and evening as another weather system moves down from the north – expected to bring more rain early next week.
Southern Waikato, Hawke’s Bay south of Wairoa, Taranaki (including Mt Taranaki), Whanganui and the eastern hills of Wellington could see some downpours or heavy rain on Sunday.
“Auckland definitely isn't out of the woods yet. There's going to be more periods of heavy rain,” Corrigan said. “But we're not expecting you know the record-breaking rainfall intensities that we saw last night.”
Looking to next week, this low will delivers a feed of rain and heavy showers through the upper North Island during Monday and Tuesday, spreading slowly southward on Wednesday and Thursday, MetService warns.
Rainfall was likely to reach warning criteria in Northland on Monday and Tuesday and may also affect Auckland and Coromandel Peninsula.
During Tuesday and Wednesday, there is a moderate risk of rainfall reaching warning criteria about western parts of Bay of Plenty and the Tasman Region, which spreads over much of the central North Island on Wednesday.
During Wednesday and Thursday, rain is expected about western parts of the South Island is affected, with a chance of heavy rain for central and southern Westland and northern Fiordland.
Strong southeasterly winds were expected through the Cook Strait, Corrigan said.