• An avalanche risk warning has been issued for the next 48 to 72 hours across the country, including Mount Cook, Nelson Lakes, Tongariro and Taranaki areas.
• Power company advises Cantabrians to be prepared for a power cut.
• Clutha civil defence officials are on stand-by, with a heavy snow warning in place for inland parts of Southland and Clutha.
• There are also snowfall warnings in place for the rest of Otago, and for inland parts of South Canterbury south of Fairlie, including the MacKenzie Basin.
• Flooding has been reported on State Highway 1 between the Waimate Junction and Oamaru and State Highway 1 at Morven near Waimate.
• Snow showers are expected tonight on Lewis Pass, Arthur's Pass, Porters Pass, Lindis Pass, Milford Road and the Dunedin to Waitati Highway.
A heavy snow warning is in place for parts of Southland, Otago and South Canterbury and some main roads have closed. Motorists are urged to take care and drive to the conditions.
Heavy snow was forecast to hit inland Otago and Southland today and Dunedin residents should prepare for freezing temperatures and snow from tomorrow, the MetService says.
MetService meteorologist Lisa Murray said a heavy snow warning had been issued for inland parts of Southland, Otago and South Canterbury, south of Fairlie, with between 20cm and 30cm of snow expected above 400 metres today. Ranfurly's elevation is 430m.
"We are giving people a heads up because it could be quite significant, especially for people in inland areas - they could get caught out and be stranded for a few days, so we are trying to get people to be prepared and get their supplies in.''
In the Clutha district, rain was expected to turn to snow above 200 metres, the local council advised. In the 12 hours from 8am today, expect 15cm to 25cm to accumulate above 400m, with 5cm to 10cm possible down to 200m. Blizzard conditions were likely in exposed areas, it said.
Contracting teams were busy on many local roads and state highways on snow ploughs and gritting trucks, the New Zealand Transport Agency advised. Journey manager Lee Wright said people should drive to the conditions, as more snow is forecast in places including alpine roads the Lindis Pass, Lewis Pass and Porters Pass.
"Please check the MetService for updates. Those travelling through alpine passes or travelling in the south of the South Island and inland areas should carry chains regardless and know how to put them on. Chains are for the driver's and road users' safety, so please ensure you have them and know how to put them on. Allow extra time."
While there was no signs of snow in the North Island today, it was a different story tomorrow.
There would be snow 600 metres above sea level in Gisborne, Wairarapa and Hawkes Bay.
On the Desert Rd snow would be expected at 700 metres above sea level.
"It will certainly be close to freezing in the evening," Flynn said.
Avalanche risk warning
An avalanche risk warning has been issued for the next 48 to 72 hours across the country, the New Zealand Avalanche Advisory stated.
The areas of high risk include Mount Cook and Nelson Lakes.
Tongariro and Taranaki also had warnings issued.
"Our forecasters are predicting some lower altitude regions to have and avalanche risk in the next 48 - 72 hours which is pretty uncommon.
"Places that normally may never have a risk are now potentially vulnerable to slab avalanches," New Zealand Avalanche Advisory forecaster Trevor Streat.
He said it was likely a cycle of "loose wet snow avalanches" at lower elevations when the temperature rises.
"This could affect roads and tracks traversing steep terrain or cutting beneath bluffs that don't usually have a problem. People need to consider how much snow is sitting on the slopes above before moving out on the first day that things warm up," he said.
He said this could affect roads and tracks in places where drivers would not expect avalanches.
Slab avalanches were more likely in high snowfall that occurred in steep terrain and over a short period, he said.
"Storm Slab avalanches are typified by heavy loading in a storm. Once this is warmed up as the storm passes, it can become very unstable. This could include traditional farming regions of the South Island that are potentially due to get loaded from a south to south-east weather flow in the coming days."
The Mountain Safety Council advised backcountry skiers, snowboarders, climbers and trampers the next week could be a very dangerous time to explore the backcountry in certain parts of the country.
"We know it's an exciting time, and the snow is finally here, just make sure you're making good decisions. It's about having a great time and making it home to your family."
Power outage warning for Christchurch area
Christchurch-based electricity distribution company says it is ready and waiting to respond to any black outs caused by snow in the next few days.
Power company Orion advised Cantabrians to be prepared for a power cut.
Residents in remote rural areas should be prepared to be without power for longer, chief executive Rob Jamieson said.
"Our people are very experienced in responding to storms, and they are on standby to respond immediately if the power supply is affected in the next few days with the forecast snow," Orion chief executive Rob Jamieson said.
"If significant snow falls, some power cuts are likely. While we will do what it can to get the power back on quickly, and have response plans in place, conditions may hamper progress."
Often the majority of power cuts during storms were caused by trees falling into lines, Jamieson said.
Tree owners were advised to keep trees and branches clear of power lines.
What can people do to prepare for possible power cuts due to the forecast snow storm?
• Keep a torch, battery radio and warm clothes handy. To reduce the risk of fire use torches instead of candles.
• Stock up on batteries for your torches and radio, have spare blankets to hand, and charge your mobile phone in advance.
• You should also have a plan for cooking food, such as on a barbecue or portable gas cooker, and check your gas bottles are full.
• To avoid the possibility of electrocution of those working on the lines, we ask that anyone installing a generator to the mains supply have this undertaken by a registered electrician. An incorrectly installed generator may send power back into the electrical network while it is being worked on by linesmen resulting in electrocution.
• Listen to the radio for Civil Defence messages and arrange to go and stay with someone else if necessary. We encourage people to seek assistance from friends, family or neighbours if needed.
• If you are medically dependent on electricity, you need an emergency plan. Obtain medical advice and inform your electricity retailer.
• If you use prescription medicines, please check that your supply is up to date.
• Please keep a safe distance away from downed lines and treat them as live at all times. We appeal to people not to try and remove trees and branches from power lines.
• To report a downed power line, call Orion on 0800 363 9898. To report a power outage, contact your electricity retailer. To report an emergency please call 111.
• If you are without power we suggest you temporarily unplug electrical appliances to avoid potential damage from voltage fluctuations that may occur when power is first restored. Keep a single light on so you know when the power returns.
If calling Orion about your power supply, ideally have your ICP number (which can be found on your power bill) available.
Dunedin set to shiver
A complex low-pressure system was expected to move on to the country from the South Tasman Sea today then move northeastwards across New Zealand tomorrow and Friday, bringing rain to many parts of the country and snow to low levels in the South Island's east.
A cold air mass was expected to hit Dunedin tomorrow, pushing temperatures down to freezing and heralding two days of snowfalls.
A blanket of snow would cover the hills surrounding the city, and snow could settle in central Dunedin. A "snow day'' for Dunedin residents was more likely on Friday than tomorrow, she said.
When the cold air mass arrived, the temperature in central Dunedin was forecast to fall to zero overnight and at Dunedin Airport could plummet to -5degC before dawn.
The maximum temperature in central Dunedin on Saturday would be 5degC. "It's going to be coooooold ... so wear your hat, gloves and scarf - the whole shebang,'' Ms Murray said.
Roads and transport
The Milford Road (SH94 Te Anau to Milford Sound) is closed from Hollyford, NZTA said. The Danseys Pass Road is also shut.
There is snow and ice between Kawarau Falls, near Queenstown, Otago and Lumsden in Southland (SH6).
Caution is needed when travelling from Dunedin to Waitati (SH1), Fairlie to Twizel (SH8) and the highway to Aoraki/ Mt Cook (SH80). Snow will also affect all alpine passes throughout today and overnight.
• Check major road conditions on the NZTA website
Chains are essential on the Crown Range Road linking Queenstown and Wanaka. All other roads are open and people should drive to winter conditions as widespread snow is forecast today, the Queenstown Lakes District Council said.
Queenstown Airport said there could be flight disruptions due to conditions today. Passengers should check online at queenstownairport.co.nz for updates.
MetService road snowfall warnings
• Lewis Pass (SH7): Snow showers are expected to return this evening and 2 to 4cm may settle between about 6pm and 8pm. Further snow is expected tomorrow with 10 to 15cm likely between dawn and 6pm Thursday above 600 metres and lesser amounts down to 200 metres.
• Arthurs Pass (SH73): Snow showers should clear this morning but one or two may return this evening. Another 1 to 2 cm may settle about the summit.
• Porters Pass (SH73): Snow showers have cleared this morning. Snow is expected to return overnight and last into Thursday evening. 10 to 20cm may settle above 600 metres during Thursday with lesser amounts down to 200 metres.
• Lindis Pass (SH8): Snow is expected to ease later this afternoon. A further 10 to 20 cm is likely to settle about the higher parts of the road by then. Occasional snow showers are possible overnight before clearing tomorrow morning and a further 1 to 2cm may fall.
• Haast Pass (SH6): Any remaining snow showers should clear this morning. Little, if any snow should settle on the road.
• Milford Rd (SH94): Snow should clear about the tunnel late morning, and a further 1 to 3cm may settle by midday. South of lake Gunn, snow showers should also clear soon after midday but a few light showers could return this evening before clearing overnight.Dunedin to Waitati Highway (SH1): Rain turning to snow Wednesday morning, with 5 to 10cm likely to accumulate on the road through to Wednesday night. Note, further snow possible early on Thursday.
• Dunedin to Waitati Highway (SH1): Rain may turn to snow late morning or afternoon and 5 to 10cm could accumulate on the top of the road before easing overnight.
NZTA State Highway area warnings
• SH1 South of Oamaru - Surface flooding is affecting the road near Alma Rd & Robins Rd. Please take care if driving in the area.
• SH63 Renwick to St Arnaud - The road is now open to one lane. Care is still needed by road users.
• SH8 Fairlie to Twizel (Burkes Pass) - The road is now open to all vehicles
• SH73 Springfield to Arthurs Pass village (Porters Pass) - The road is open to all traffic.
• SH73 Arthurs Pass village to Otira (Arthurs Pass) - The road is now open to all traffic
• SH7 Hanmer Springs turn-off to Springs Junction (Lewis Pass) - The road is now open to all traffic
• SH8 Tarras to Omarama (Lindis Pass) - The road is open to all traffic
- additional reporting Shawn McAvinue