Weather system results in power cuts, road closures and thunderstorm warnings

MetService has cancelled more than a dozen weather alerts across the country, as a front moves away to the east of the country.

The country has been lashed by wet and wild weather over the past two days, causing slips, power outages, localised flooding and downed trees.

MetService says heavy rain warnings are cancelled across the North and South Island in areas like, Auckland, Tasman / Nelson, and Bay of Plenty.

Strong wind watches in the North Island have also been cancelled, though a severe thunderstorm watch is in place for the Rotorua, Bay of Plenty, and Gisborne areas.

Its head of weather news Heather Keats says parts of the western Tasman District recorded some of the heaviest rainfall on Tuesday.

Some of the higher located weather stations have recorded 270 millimetres of rain over a period of 36 hours, she told Morning Report.

The rain band is still sitting over the Coromandel Peninsula. In the ranges around 175mm fell while low-lying areas such as Whangamatā received 170mm.

"So yes there has definitely been a lot of rain moving over the country but fortunately that rain band is starting to clear. It is just going to continue to affect Bay of Plenty and it is yet to clear the Coromandel Peninsula."

Keats expected the weather to have cleared by 1pm.

Meanwhile, Bay of Plenty Civil Defence has been receiving reports of localised flooding, as rain continues to lash the region.

Lines company Horizons Network is also reporting hundreds of outages in eastern Bay of Plenty.

At its worst, 883 properties were out. That's now down to 212.

Powerco, which connects western Bay of Plenty, is reporting some outages.

Disruption on roads too

Motorists have been warned to take extra care in Bay of Plenty with some key highways closed.

A milk truck rolled on Tuesday night, shutting a section of State Highway 2 near Matatā.

The driver suffered moderate injuries.

Meanwhile slips closed State Highway 30 at Lake Rotoiti and State Highway 33 at Okere Falls.

There were downed trees and blocked drains across the region, Bay of Plenty Civil Defence duty controller Nassah Rolleston-Steed told Morning Report.

The New Zealand Transport Agency is urging motorists in Waikato to be cautious, with heavy rain making it hazardous to travel.

It says the several potholes have formed on the Waikato Expressway, with crashes causing significant delays.

There's also a lane closure on State Highway 31 at Kawhia road and crews are at the scene.

NZTA is urging drivers to slow down and drive to the conditions.

In Northland, NZTA has confirmed all highways are open this morning, but delays are possible on SH1 over the Brynderwyn Hills as a result of yesterday's slip.

The roading agency says both lanes are currently open in the Brynderwyns but tree removal between 11am and 3pm will mean traffic will be reduced to one lane with stop/go management at times.

Both lanes will be closed for short periods as trees come down.

NZTA says motorists should expect delays.

Warning on flooded land due to dam spillage

Water needs to be spilled from the Matahina Dam due to the heavy rainfall which has led to a warning of possible flooding to land alongside the Rangitāiki River.

Significant rainfall has been recorded in the Rangitāiki catchment over the past 24 hours, the Bay of Plenty Regional Council says in a social media post.

As a result, current river inflows into the Matahina Dam exceed generation capacity and Manawa Energy has decided water will be spilled from the dam. The increased river flow means that floodwater could cover land immediately beside the Rangitāiki River, the council says.

The council is advising that stock on low-lying land immediately beside the Rangitāiki River and particularly in areas upstream from Te Teko be moved to higher ground, due to a risk of flooding.

This warning does not apply to areas protected by stopbanks and the council says there is no risk of flooding in Edgecumbe or the Rangitāiki Plains area.

Regional council staff are monitoring the situation closely and will provide further advice, as required.

Savings for Watercare

Auckland's water provider Watercare says the city's dams are overflowing after recent months of heavy rain.

The water supply dams have filled to 100 percent for the first time since 2023, with last dam overflowing in Wairoa at 11.30pm on Tuesday.

Head of water Sharon Danks told Morning Report it means Watercare can run the water supply more efficiently.

"The Waikato River plant costs about five times more to run than our Ardmore treatment plant which relies more on gravity so there's some cost efficiencies for us.

"It also means that we're confident now we'll make it through next summer without having to go into drought restrictions as well."

It was hard to quantify in dollar terms, however, it could save watercare between $500,000 and $1 million, but it wouldn't lead to cheaper water bills for Aucklanders.

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