Labour Day weather: Cold snap brings heavy rain, snow and strong winds across South Island

Between 60 and 90mm of rain is forecast, with the potential for up to 130mm of rainfall, which could cause more flooding and slips – and quicker than anticipated with higher than usual river levels and sodden land after earlier rainfall, NZTA Taranaki and Manawatū/Whanganui system manager Liesl Dawson said.

Dawson urged motorists to drive to the conditions and be alert to the possibility of more flooding, slips, debris and tree branches on the road, and to keep an eye on NZTA’s Journey Planner “as short notice closures may be a possibility”.

“The road is open but people need to be prepared for extensive delays. SH3 near Awakino and SH4 near Taumarunui have seen a lot of rainfall over the past fortnight.

“Please take extra care; and consider moving your trip forward to avoid the forecast rain. If you are travelling on these roads, please also expect significant delays as many areas remain under stop/go traffic management as crews continue the cleanup from the past fortnight.“

MetService forecaster Josh Griffin told the Herald a complex trough from the Tasman Sea would move across New Zealand today.

“We are expecting some heavy rain in the western parts of the South Island,” he said.

“Pretty much everywhere in the country is going to get some rain or showers.”

While the bulk of the heavy rain would miss Northland and Auckland, Griffin predicted there’d still be some from late afternoon onwards.

“There is also a risk for thunderstorms, particularly around parts of Northland, in the evening,” he told the Herald.

A heavy rain warning is in place for the ranges of the Westland District north of Haast until 6pm, where up to 200mm worth of rain is forecast to fall.

Heavy rain warnings are forecast to come into force this morning for the headwaters of the Canterbury lakes and rivers and the top half of the South Island from this morning until late this evening.

In the North Island, heavy rain warnings are set to begin from this afternoon until early tomorrow morning for the Tararua Ranges and the central North Island hill country.

Strong wind watches are forecast for the lower North Island from this afternoon until late this evening, with gusts set to reach 120km/h in certain areas.

Road snowfall warnings for alpine roads are forecast to begin early this morning until late this evening.

MetService has issued a heavy snow warning for the Canterbury High Country south of SH73 from 2pm until 9pm.

Griffin said there was a risk of flooding in the areas under heavy rain warnings.

“Since we have had the heavy rain in the last week, some of the ground is already going to be saturated,” he said.

“There will be a potential for surface flooding or streams and rivers to rise rapidly as well.”

The National Emergency Management Agency (Nema) is urging people to “be extra vigilant” and delay their long-weekend travel plans if needed.

Chief executive Dave Gawn said “it’s essential that people factor [the warnings] into their travel plans”.

“Plan your journeys, pack extra supplies in case you get stranded, and if it’s looking really hairy, consider delaying your travel if you can.”

Gawn said councils, Civil Defence, emergency services and government agencies across the country are working together to coordinate a response.

It includes the National Crisis Management Centre being called in to the Beehive to assist with response and recovery efforts.

Wellington City Council has urged residents to stay away from the forested areas of the Town Belt and other parks and reserves where there are tall trees.

This follows the tragic death of a walker hit by a falling branch on Mt Victoria during last week’s storms.

The council said winds could damage trees, power lines, and unsecured structures, while driving may be difficult, especially for high-sided vehicles and motorcycles.

“There’s an increased risk that trees or branches may come down.

“Begonia House in the Botanic Garden will be closed [today] as a safety precaution.”

Griffin said the worst conditions would pull away and the weather would begin to ease tomorrow.

“On Tuesday, there will be some remnants of the complex trough affecting parts of the North Island.

“As that feature pulls off to the east tomorrow, as we go into Wednesday, there will be a minimal risk of severe weather.”

However, Niwa warns the chill will spread over the North Island on Tuesday.

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