Severe rain breaks records in Northland, closes highways and floods areas

A cleanup is under way at the slip site on State Highway 1 in the Mangamuka Gorge. The road is currently closed, and detours are in place. Photo / NZ Transport Agency

Northland has swung from one extreme to the other after drought conditions in March quickly turned to record-breaking rainfall.

Kerikeri was doused by 528mm of rain in April, surpassing the amount of rainfall the Far North town usually sees in the first four months of the year.

Further south, Whangārei received 402mm of rain that same month, more than quadruple the average rainfall of 96mm.

MetService meteorologist Mmathapelo Makgabutlane said April had been the wettest month for Whangārei since records began in 1943, and for Kerikeri since records began in 1978.

Weather systems from the north were behind the downpours. They brought warmer, moist air and heavy rain that caused slips and floods throughout Northland.

Floodwaters caused by heavy rain closed State Highway 1 at Cape Rēinga for five hours on Tuesday afternoon.

Later that evening, State Highway 1 through the Mangamuka Gorge closed after a slip blocked the main route north to Kaitāia.

The closure was the second in three days. The first was during Sunday’s torrential rain.

NZ Transport Agency Northland and Auckland regional manager for maintenance and operations, Jacqui Hori-Hoult, said minor overslips were expected from time to time because of the gorge’s challenging geology and varying terrain.

She said they were generally easier to manage than the more complex underslips that were repaired after severe storms closed the gorge in 2022.

The road was still closed yesterday afternoon with SH10 an available detour.

The Mangamuka Gorge was not the only portion of SH1 to suffer from April’s weather.

Ex-tropical Cyclone Tam caused a slip on the Brynderwyn Hills on Easter Sunday, briefly closing the southbound lane.

A vehicle was hit by falling debris, leaving the driver shaken but unhurt.

However, rural roads appeared to bear the brunt of April’s rains.

Many, especially in the Far North, flooded as rivers swelled from three weeks of rain.

The Waiomio Valley was cut off to all cars except for 4x4 vehicles after recent heavy rain on Tuesday. Photo / Roddy Pihema.

Winter was still a month away, but already people were feeling the strain of the unusually heavy downpours.

Bay of Islands-Whangaroa Community Board member Roddy Hapati Pihema said the wet weather was particularly stressful for people in rural areas.

“ ... As they can often become cut off from the main towns and family, not to mention resources.

“No roads often means there is no way to see doctors or do shopping. Children can’t make it to school or course, then there’s the fact that they can’t get to their place of employment.”

Pihema said communities were working with Civil Defence to prepare for different weather events.

Locals with a strong knowledge of their areas, such as Pihema, regularly checked river levels, culverts, and made welfare checks at freedom camping spots.

He said while residents were a “strong breed” who knew how to sustain themselves, more could be done to provide future resilience.

Pihema believed a lot of stress would be relieved if more funding for capital works was available to seal and lift roads in rural communities.

Hori-Hoult said NZTA planned to undertake resealing and resurfacing at a large number of sites, as well as drainage improvements.

She said crews would monitor the network for potholes and damage and respond as quickly as possible.

The Kawakawa catchment, where the Waiharakeke, Otiria and Waiomio Streams meet, was swollen from recent downpours. Photo / Roddy Pihema

Pihema praised local government’s efforts to ensure resilience, saying it was doing “exceptionally well”.

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Corks Rd in Tikipunga was subject to flooding after a thunderstorm on Sunday. The nearby stream burst its banks and left some vehicles turning around instead of risking the floodwaters. Photo / Brodie Stone

Research commissioned by AMI, State and NZI Wild Weather Tracker showed more than half of New Zealanders have experienced anxiety over storms and heavy rainfall.

The research showed Northlanders had lodged the fourth-most claims for natural hazard events nationwide between last September and February. Otago lodged the most.

Northland Civil Defence Emergency Management Group spokesman Zachary Woods said many areas in Northland had flood-prone roads and farms.

He encouraged people to know the risks and have a plan, plus keep up to date with the weather.

Woods said there were community-led Civil Defence centres and other Civil Defence centres that opened during adverse weather if required.

*This story has been updated to clarify that Kerikeri’s rainfall records began in 1978, not 1943.

Brodie Stone covers crime and emergency for the Northern Advocate. She has spent most of her life in Whangārei and is passionate about delving into issues that matter to Northlanders and beyond.