The bitterly cold blast that has hit New Zealand this week should ease off over the coming days, but heavy snow is still expected overnight in many areas, including Wellington and Christchurch.
Snow returned to the nation's capital this afternoon, with a late afternoon surge seeing the the temperature plunge to just above freezing with a wind chill of -5, according to weatherwatch.co.nz
The polar surge in the capital forced police to close roads, including the Rimutaka Hill Road, Wainuiomata Hill Road, Paekakariki Hill Road, and State Highway 58 between State Highway 2 to Moonshine Road and Blue Mountains Road in Upper Hutt.
Police said driving conditions were treacherous and people should only travel if it was essential.
Extreme caution was needed on all roads in and around the Hutt Valley.
Head weather analyst Philip Duncan said the snow will spread across the lower North Island tonight, although some main centres to the north west of the city may avoid the worst snowfalls.
"Snow is expected to be heavy around Wellington, Upper Hutt and Wairarapa tonight with a moderate risk of snow flakes returning to low levels of the lower North Island like Wanganui and Taranaki".
Heavy snow in Wellington is expected to come and go all night with snow easing tomorrow morning.
While Gisborne took the national high with 13 degrees today, snow is forecast to move into the Hawkes Bay and Gisborne regions, to 100 or 200 metres.
Mr Duncan said that the city and region had so far missed the worst of the weather but the southerly will fire up the east coast of the North Island across Hawkes Bay and Gisborne tomorrow.
Christchurch and other coastal parts of Canterbury are also expected to see more snow tonight.
Weather analyst Richard Green said snow showers may return to the city tonight, but should ease in the early hours of tomorrow morning.
Snow isn't expected to be as heavy as it was yesterday with passing snow flurries, but he said there was still a strong chance there would be some falls.
"The freezing level has lifted just enough so that Christchurch, Timaru and Ashburton are all on the borderline of snow. It's an extremely fine line between sleet, rain and snow for those centres tonight but we don't expect the falls to be long lasting and heavy as they were last night".
A few brief snow flurries are possible further south in Dunedin, but conditions there should be easing, while Auckland's chance of seeing more snow is quickly fading.
Graupel and sleet fell in some areas this afternoon, while snow was confirmed on the tops of the Waitakere Ranges.
Light rain showers are expected to move in to the city again tonight as a very small low tracks by but snow is not predicted in the CBD.
Farmers and their stock coping in snow
The polar blast is making life difficult for farmers but they are coping, despite some having to work their stock in thick snow for the first time, Federated Farmers adverse events spokesman David Rose says.
"It's very unusual for a storm to affect absolutely the whole country. In some areas, particularly in the lower North Island, farmers wouldn't have had to deal with a weather event like this before,'' he said.
In some regions, particularly Canterbury and Wairarapa, farmers would be hoping the snow cleared before it turned to ice, which would make it impossible for stock to graze.
"They'll be hoping for a bit of sun or even, dare I say it, a bit of rain, which actually gets rid of snow quite quickly,'' he said.
"The worst thing that could happen is if it freezes. If that happens it will take a lot of warming up before it melts. If we get a lot of overcast days and it stays ice they'll have to feed their stock completely on supplement, and that's a huge job.''
Lambing had started in some areas so there would have been some stock losses.
It was fortunate the storm didn't hit later in the season, which could have had devastating consequences, Mr Rose said.
With calving also beginning to get underway, dairy farmers were putting their cows behind shelters and doing what they could to protect them from the elements.
"Lambs and calves are incredibly robust. Even if it's cold for us humans, it takes just a few days of settled weather for them to find their feet.''
Better weather expected
The bitterly cold polar blast that blanketed much of the South Island in snow and brought record low temperatures to Auckland is set to ease over the next few days, forecasters say.
Met service said threats of intense snow will lower as a ridge approaches from the Tasman Sea and moves onto southern New Zealand tomorrow.
Snow showers were still likely in higher areas between Gisborne and Canterbury but were not expected to reach warning levels by Friday, it said.
What's the current weather forecast? Click here for the latest.
A weather historian says the polar blast has been a 'once in a life time' event.
Erick Brenstrom told Newstalk ZB the recent snow falls are similar to the massive storm of 1939, but temperatures were "a wee bit colder and the sheer quantity of snow was a lot worse" in the 1930's event.
"In Auckland, for example, in 1939 you had 5cm of snow lying on top of Mt Eden, as well as snow falling in the suburb like Ponsonby, Remuera. And it also snowed at the lighthouse at the very top end of the North Island. It snowed in Dargaville, Ruapekapeka up in Northland. There was also three hours of snow Gisborne City - so there were snowball fights there. In Banks Peninsula and Otago we had snow drifts of 10 metres."
"That one was worse than the one we're having now.
Lucky tourists
Two American tourists have had a lucky escape out of a snow-covered Whirinaki Forest Park in the central North Island.
The pair had spent a night in the Central Whirinaki Hut but efforts to get to another hut were hampered by the cold conditions.
Two off-duty police officers heading out for an overnight hunting trip located the pair and were able to call for assistance.
Detective Sergeant John Wilson says without local knowledge it would have been almost impossible to successfully negotiate the maze of roads.
He says another night in such conditions may have had serious consequences.
Closed for business
Both Lincoln and Canterbury University were closed today.
Airports in Queenstown, Dunedin and Christchurch were closed this morning, but all have since reopened, albeit with some delays.
Wellington Airport was operating, but its website homepage crashed earlier this morning under an onrush of travellers and the airport advised them to contact their carrier.
MetService head forecaster Peter Kreft told NZPA yesterday the polar blast was "of the order of a 50 year'' event and warned it could last for several more days.
Some NZ Bus services were cancelled in the capital this morning.
The New Zealand Blood Service is calling on people in Nelson and North Island to come in and donate this week if they are eligible, to make up for collections lost after disruptions yesterday.
The Christchurch and Dunedin Donor Centres were closed yesterday and Westport and Mosgiel mobile collections were cancelled as a result of bad weather.
Canterbury Earthquake Recovery Authority closed access to the city's quake-damaged red zone and would reassess the situation this morning.
Power outages
Heavy snow cut power to 1000 houses amid bitterly cold conditions in rural Canterbury, Orion confirmed.
Areas including Rakaia, Westmelton, Leeston and Greendale were hit by the outages last night.
Orion General Manager Commercial Rob Jamieson said trees and branches falling on overhead lines were the main cause of cuts.
Crews had been assessing the damage since dawn this morning, he said.
About 750 homes in south Taranaki, Wanganui, Manawatu and Wairarapa also spent the night without power after high winds and snow caused trees and branches to tear down overhead lines.
And around 450 homes in Upper Hutt were without power this morning.
Unusual weather for Auckland
Climate scientist Georgina Griffiths of the National Institute of Water and Atmospheric Research said yesterday was the coldest day ever recorded in Auckland. The temperature got up to only 8.2C - compared with the previous lowest high of 8.7C, on July 4, 1996.
The last time snow settled on the ground in the city was 1939. It fell to ground level at the airport in 1976.
The snow caused waves of excitement in Auckland. Kevin Prohl saw a snow flurry as he was driving around Western Springs and described it as a fairy tale. "Looking at oncoming drivers and seeing their smiles as we were fascinated by this unusual occurrence - it was truly delightful to see, yet all too short."
Richard Brown, 53, has lived in Auckland his entire life and had never seen snow in the city. "It was snow, I'm sure it was."
There was even debate among weather experts as to what was actually falling.
MetService weather ambassador Bob McDavitt said most Aucklanders had witnessed "graupel" - effectively hail with a soft centre.
While many Aucklanders were delighted with the light flurry of snow - the result of weather MetService described as close to a one-in-50-year-event - the high winds created havoc. Four people were injured when a tree toppled on to a house in Pakuranga.
Not so fun for some
The cold snap also wreaked havoc further south including the quake-devastated eastern suburbs of Christchurch. Power was cut to hundreds of homes, mail postponed, schools were shut for the day and heavy snow made it too dangerous to drive on.
In the Wellington region, five main roads were closed and 24 crashes were reported yesterday.
"We've been getting calls from people getting stuck on the road, or cars sliding down the driveway and getting stuck in the gutter. We've got quite a lot going on," Inspector Ken Climo of the police said.
Prime Minister John Key commented on "the very uncharacteristic weather" during his post-Cabinet press conference.
Describing the capital as a "winter wonderland", Mr Key said it was the first time he could recall seeing snow fall in downtown Wellington.
"My wife tells me there is snow around our house [in Parnell, Auckland]. It's very unusual, and the main message to New Zealanders is just to be cautious and a little bit careful - make sure they keep an eye out for their family and friends, and if they are aware of their neighbours living alone, it might be a good idea just to check up on them and make sure everything is OK."
- NZPA, HERALD ONLINE
