Highways shut as heavy snow, rain and winds hit the South Island

Heavy rain, ice, and snow are hitting the South Island as a cold front settles in.

MetService said there had been heavy rain overnight along the east coast of the South Island and the snow level had dropped to 400-500m above sea level.

Heavy snow warnings were in place around midday on Tuesday for the North and South Canterbury high country regions, and the foothills about and south of the Rangitata River.

A strong wind warning was in place for Westland and the Grey District and a heavy rain warning in North Otago.

MetService had a heavy rain watch in place for the Canterbury Plains, Eastern Marlborough and Wellington regions also.

MetService late on Tuesday morning extended several snowfall warnings for a number of South Island highways

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Up to 60 centimetres of snow was expected to settle on State Highway 73 at Porters Pass through until 9pm tomorrow, with more to fall higher up.

While in Lewis Pass, between eight and 15 centimetres of snow was expected to fall on the road before 11pm Wednesday night.

In Arthurs Pass, up to 10 centimetres of snow was expected to settle near the summit, through until 6pm Wednesday.

Less snow was forecast in the Lindis Pass, though a snowfall warning remained in place until 3pm.

A snowfall warning for the Milford Road was lifted, with no further snow expected to affect the road.

SH8 between Lake Tekapo and Fairlie was closed earlier due to snow, but has since reopened. SH80 from Lake Pukaki to Mount Cook remained closed about midday.

Ashburton District Council said the road to Ashburton Gorge, near Mt Somers would be closed about 5pm as a precautionary safety measure due to heavy snow. Access will remain in place for residents and conditions will be reassessed after the road is cleared by a grader on Wednesday morning.

Mt Dobson Ski Area was closed on Tuesday but said it had received 40 centimetres of snow overnight, with more falling.

Cardrona Alpine Resort was open, having received 38 centimetres overnight and Mt Hutt had 25 centimetres of fresh snow at its base on Tuesday afternoon.

Selwyn District Council have also issued a conserve water notice for the Arthur's Pass Water Supply.

Strong winds

Westland and the Grey District should expect strong winds from 9am, with gusts of up to 140km/h expected later on Tuesday. MetService said severe easterlies could damage trees, powerlines and unsecured structures.

Similar wind warnings are also in place in Fiordland until Wednesday morning.

West Coast Civil Defence said homeowners should secure items on their property.

There were also a number of yellow snow watches throughout the South Island and yellow rain watches for parts of Bay of Plenty, Tasman and Taranaki.

Forecasters last week warned the warmer temperature would drop as a polar blast hit this week.

MetService meteorologist Mmathapelo Makgabutlane told Morning Report there had been heavy snow fall on Mount Cook overnight and more snow was expected today around Southland, Otago, and the Canterbury high country.

Dunedin could see snow on the hills, down to 200m, she said.

"Quite a bit of snow, quite a bit of everything really. We are expecting it to impact on people like farmers as well as road users."

The North Island should expect the front to hit on Wednesday and Thursday, and MetService was keeping an eye on possible rain for Hawke's Bay and Tai Rāwhiti, Makgabutlane said.

The cold blast was expected to stick around most of this week, though it should clear out of the South Island by late on Thursday.

"It does look like into the weekend most of the North Island should be back into fairly settled conditions."

Waka Kotahi NZTA systems manager Mark Pinner said SH8 from Lake Pukaki to Fairlie and SH80 between Lake Pukaki and Mount Cook were closed Wednesday morning due to snow.

He said there was a chance SH73 may close too with up to 50cm of snow forecast.

Crews had been out throughout the night with de-icers and grit, Pinner said. But people should take care and check ahead.

"For the drivers its watch those conditions, watch our website. If we need to close the road because we think it's not safe, then we do close the road."

Mount Cook Road, the only route in and out of the Aoraki, was shut early on Tuesday morning.

Duty manager at Mount Cook's Hermitage Hotel Samira Yeddou said guests were unable to check out because of conditions.

"We might provide a late check-out to all the guests, so they probably remain in their rooms until one o'clock or two o'clock, and then we can check out them or they can extend. It's up to them."