Big snow dump hits the country (+pics)

Three unusual weather events have combined to create a "polar outbreak" bringing some of New Zealand's heaviest snow in years.

Snow fell in areas of the Wellington region and on the Desert Road last night, while the South Island continues to shiver in the cold snap.

Snow was reported to have fallen on the Rimutaka Hill Road between Wellington and Wairarapa and in the Kapiti Coast township of Paekakariki.

While MetService forecaster Ian Miller was dubious of reports of snow in the seaside town, saying it was probably 'just hail' Kapiti mayor Jenny Rowan said she was amazed to see the paddocks of her Paekakariki lifestyle block covered in drifts of white snow last night.

Meanwhile residents in the hilly suburbs of Christchurch were struggling to get to work this morning after snow overnight left some streets accessible by four-wheel-drive only.

At 9am it was snowing steadily in central Christchurch and children at Cashmere Primary School in the hill suburb were told to stay at home for the day because of the snow.

Many roads around Banks Peninsula and Port Hills had been closed by snow and ice.

A severe weather warning was renewed yesterday for snow until around noon today, with snow showers about Otago Peninsula and Banks Peninsula and a burst of heavy snow on the central North Island plateau.

MetService spokesman Bob McDavitt said 3.5 metres of snow pack had been recorded at Whakapapa ski field on Mt Ruapehu - which was the deepest snowfall there since 1992.

Staff at Whakapapa and Turoa ski-fields have reported on their website that they are "snowed under" with work, with patrollers on "the immense task of avalanche control whilst everyone else will be digging".

Snow also fell in the Wairarapa town of Featherston and MetService said snow showers were forecast for the Rimutaka Hill Rd till about 3pm today. Around 5cm of snow was expected to fall near the summit.

Further north, up to 15cm of snow fell on the Desert Rd over night, and another 3-5cm forecast for this morning.

The streets of Dannevirke were also covered with snow this morning.

The snow was caused by air from the Southern Ocean moving onto the Tasman Sea before being diverted onto the western parts of the central plateau, Mr McDavitt said.

Southern parts of the North Island could expect the southerly to get stronger before it faded out, he said, with southerly gales forecast for Cook Strait tonight.

Heavy rain warnings have been issued for the south and east of the South Island and for the southern and central parts of the North Island.

Snow was forecast tonight for the Lindis Pass and Porters Pass in the central South Island.

The southerly is expected to be gone by the weekend.

A fast-moving storm lashed the Kapiti Coast and north Wellington last night, with about 32 lightning flashes recorded by MetService.

A southerly change triggered the thunderstorm, which swept up the west coast of the North Island.

Mr McDavitt said snowfalls had been heavy for three reasons:

The Tasman Sea had become a "breeding ground" for low-pressure systems since mid July.

The lows had often moved slowly, allowing more time for snow or rain to fall.

Cold air from the Southern Ocean had been drawn north and then over New Zealand, tipping the balance toward snow and away from rain.

The Department of Conservation's Turangi-Taupo area manager Dave Lumley said only experienced people able to evaluate avalanche hazards should be carrying out backcountry skiing, and alpine trampers should be particularly cautious and make sure they get up-to-date avalanche information.

"Travel in the back country should be limited to low angle terrain well away from any avalanche terrain," he said. A website (www.avalanche.net.nz) which posts up-to-date details on avalanche risks around the country has many regions rated as high risk.

DOC's warning followed a rough weekend in the South Island where nine people were rescued from mountain areas which were hazardous, and alpine safety experts have spoken out about foolhardy expeditions into the backcountry.

- with The Press and NZPA

- © Fairfax NZ News