Cold front causes chaos, avalanche warnings across the South Island

A cold front has swept across New Zealand in the past 24 hours, leaving motorists stranded, closing schools and bringing a heavy dusting of snow on ski fields.

Some highways across the country have since reopened, with a warning that there will be ice on the roads in the coming days.

The fresh snow was a welcome sight at Temple Basin in Arthur's Pass and ski area manager Elliot Smith said it meant the upper terrain would open for the first time this season.

"It was pretty wild last night, we had southeasterly gusts up to 90km and we got 25cm at the lodge and about 40cm of snow so we're looking to open the skifield."

More snow was forecast for Thursday, then more again next week, which Smith said could make it a good August for the skifield.

But the heavy snow prompted the NZ Mountain Safety Council to issue avalanche warnings across the South Island.

Avalanche Danger ratings have risen to high for Aoraki/Mt Cook, Two Thumbs, Craigieburn, Nelson Lakes and Tongariro.

Back in Arthur's Pass, Flock Hill Lodge manager Andrew Cullen said about 25 stranded motorists were rescued from State Highway 73 yesterday afternoon.

"We took the farm vehicles out with chains on at about 4.30pm yesterday. We had people that got stranded sort of about 2km down the road, but we've ferried them back here and fed them and put them up"

One driver decided to take a caravan over Porters Pass after being asked to pull over and wait, which was part of the reason the highway remained closed.

It had to be safely removed from the narrow road before it could be re-opened to two lanes.

Cullen said those in the pass were geared up for whatever Mother Nature might throw at them.

"People shouldn't have been driving through, they would have driven through two or three road closure signs.

"Even the people here were very much like 'we just wanted to get home', but when you're in an alpine pass you need a little bit more respectful of the warnings that are out there and what people have been told."

It stopped snowing in Arthur's Pass this morning, and by 3pm, the road had reopened as had the Lewis Pass, reconnecting Canterbury with Nelson and the West Coast.

Further north, the Desert Road is closed again between Rangipo and Waiouru with a detour in place.

MetService meteorologist Lewis Ferris said high-elevated areas could still be impacted.

Strong winds have also been recorded from Wellington to Mahia Peninsula.

"That cold southerly will move away, some light winds will be around the country and tomorrow that temperature will bounce back up."

Farmers struggle to keep livestock alive

Some farmers in the central North Island are working to keep livestock alive amidst snowfall.

Rangitikei District councillor Gill Duncan said it was inevitable in this sort of weather.

She was expecting there would be a number of lambs born yesterday on her farm, east of Taihape, would have died.

"Anything that dropped last night has a high chance of not surviving because it was so cold. It was three degrees here this morning and as I say there was snow on the ground. So those lambies, their mothers need to lick them dry as soon as possible, and in snow that's virtually impossible."

Duncan said they tred to mitigate the impact by moving lambing ewes into more-sheltered paddocks.

In Gisborne, farmers are hoping the snow will clear by morning.

Federated Farmers president Toby Williams said it was more of a dusting compared to the blanketing of the central North Island.

But there's been about 10-12cm of snow in the Gisborne High Country, which is significant for the area.

Williams said if the snow hung around for more than a day, it would cover the feed for sheep and cattle.

He said farmers would be a lot more concerned if the storm was forecast as a week-long event.