MetService this evening said a band of active showers was likely to bring snow down to about 200 metres in Auckland tonight and it could affect some higher roads there.
Driving dangers
The snow that has covered New Zealand today will freeze overnight creating treacherous driving conditions, police warn.
Many state highways around New Zealand were closed, including the Desert Road and Rimutaka Hill road in the North Island and the Lewis Pass and Arthurs Pass in the South Island.
"We're warning drivers that, unlike today where the snow was a clearly visible hazard, there will be large areas of ice on the roads tomorrow, especially in rural and shaded areas, that you will not be able to see,'' Inspector Al Stewart, of Christchurch police, said.
Road users should assess their local road conditions and stay home or delay non-essential travel where possible, he said.
Motorists in Southland have also been warned they need to be aware of the risk of black ice.
Late this afternoon SH6 between Invercargill and Queenstown was still closed from Five Rivers north, as were SH93 between Clinton and Mataura and SH 90 between Raes Junction and Tapanui, but SH1 to Dunedin has reopened.
Emergency Management Southland manager Neil Cruickshank said that power had been restored to all areas in southern Southland and Stewart Island and there were no reports of problems in the parts of northern Southland that had experienced the heaviest snowfalls.
Police in the Wellington District are also warning drivers to make essential travel only tonight, as snowfalls make driving conditions extremely dangerous.
Inspector Ken Climo of the Police Central Communications Centre said a number of roads in and around the district are currently closed. These include the Rimutaka Hill Road, Paekakariki Hill Road and Blue Mountains Road, Upper Hutt.
"Traffic lights are out across the Hutt Valley and there are reports of power outages in Wainuiomata, however the Wainuiomata Hill Road remains open."
Inspector Climo said State Highway 58 (Haywards Hill) is passable but extreme caution is needed and there are reports of snowfalls on State Highway Two (River Road) and Stokes Valley, making driving conditions extremely dangerous.
"If you need to make essential travel this evening, make sure you are equipped with food, warm clothing and blankets for all occupants, in case you cannot return to your destination this evening, given the extreme weather conditions."
The Automobile Association said drivers appeared to be heeding advice to stay off the roads, with the AA breakdown service reporting fewer than normal call outs in the South Island.
"Our advice to motorists when it is snowing is always stay off the road unless you absolutely have to drive, and it seems as if people are taking that approach," said AA Motoring Affairs General Manager Mike Noon.
"Driving on snowy or icy roads is extremely treacherous even if you have a four-wheel-drive. Vehicles can lose their grip on the road very easily and once they start sliding it can be next to impossible to get them back under control. If your vehicle starts to skid on a patch of ice it is best to lightly push on the brakes a couple of times. Braking heavily is likely to put the car more out of control.
"Drivers should take particular care in the early morning or evening when wet roads can ice up and if possible avoid being on the road at these times."
The AA recommends that drivers should double their following distance from two to four seconds, reduce their speeds and make sure they can see and be seen as well as possible.
One-in-50-years event
MetService head forecaster Peter Kreft told NZPA the polar blast was "of the order of a 50 year'' event and warned it could last for several more days.
"It's a once in many decades event. We are probably looking at something like - in terms of extent and severity - maybe 50 years,'' he said.
The level of snow that fell in Wellington had not been seen since at least the 1970s, he said this morning. Heavy snow returned to Wellington this afternoon with strong flurries in the central city, while as much as 11cm was reported in Upper Hutt.
Wellington then endured bursts of lightning and thunder in the evening.
Snowflakes were falling in downtown Auckland this afternoon, a rarity for the city.
About 2000 homes in South Taranaki, Whanganui, Manawatu and Wairarapa were without power because high winds and snow caused trees and branches to tear down overhead lines, Powerco network operations manager Phil Marsh said.
About 1500 of the homes would have power restored by tonight. He warned it was likely there would be more power cuts tomorrow.
Several hundred homes in Christchurch remained without power.
Services cancelled
Many key services around the country have been cancelled.
The Southern District Health Board has postponed elective surgery and outpatient appointments at Dunedin and Wakari Hospitals today.
Canterbury University, Christchurch Polytechnic Institute of Technology, and Otago University's Christchurch campus were closed for the day and Environment Canterbury said all Christchurch metro bus services had been suspended until further notice.
Canterbury Earthquake Recovery Authority closed access to the city's quake-damaged red zone and would reassess the situation tomorrow morning.
The Ministry of Justice said a number of courts were closed across the South Island including both the High Court and District Court in Christchurch and the District Court in Dunedin.
South Island St John regional operations manager Chris Haines said its workload had been steady but not excessively busy.
It had responded to nine callouts in the South Island where people had slipped on snow or ice.
A Police Central Communications spokesman told NZPA police had been kept very busy today, but there had been no serious callouts.
Wellington Civil Defence was advising the region's residents to make sure they were prepared in the event that snowfalls keep them trapped at home for a couple of days.
"People should prepare for the worst, which means making sure they're ready in the event that they cannot leave home and may be without electricity and other amenities,'' Wellington region Civil Defence manager Rian Van Schalkwyk said.
- NZPA, HERALD ONLINE