Get set for another icy blast

Mt Ngauruhoe yesterday. Snow blanketed the Central Plateau and stretched down to the Kaimanawa Ranges. Picture / Alan Gibson

The country will remain in an icy grip in the next few days, with civil defence staff standing by for another dumping of snow forecast for the South Island.

Tomorrow is the shortest day of the year, which usually marks the start of the winter chilly season. But this year the cold weather started weeks ago. The South Island is bracing for another 15cm of snow and 800 homes are going into their 10th day without power.

Supermarkets reported customers stocking up on easy-eat meals and Canterbury Civil Defence issued an extreme weather warning, urging householders to make sure they have candles, full gas bottles and batteries.

And the North Island does not escape - heavy showers, cold southerlies, thunderstorms and possibly hail are forecast in some areas from tomorrow.

"Winter is firmly in charge around here," said MetService weather ambassador Bob McDavitt.

The cold front was expected to hit the South Island overnight and Cook Strait tonight, followed by freezing southerlies. The front is expected to intensify and deepen into a slow-moving low as it moves over the North Island tomorrow, with bad weather lasting into the weekend.

Civil defence officials hoped this snowfall would cause no more damage.

"We're hoping that's the case but we're planning for the worst," said Canterbury Civil Defence emergency management planner Jon Mitchell.

Record-breaking electricity use

The country has already broken its record for electricity use, burning through 6630MW of power between 5.30pm and 6pm on Monday, up 2 per cent on the high of 6513MW in 2004.

"It's been a rough couple of weeks," said Transpower spokesman Chris Roberts.

Transpower issued its first emergency notice of the year during the peak, asking for more power from generators and cuts from retailers.

"There wasn't a great deal more generators could offer but there was spare capacity," Mr Roberts said. "Everyone knew this winter was going to be tight."

The situation should ease when a new 385-megawatt combined cycle gas turbine at Huntly Power Station is commissioned in April, but the country has enough power.

"Unless there's a major plant failure there's no reason to expect any problem getting through winter," Mr Roberts said.

Auckland power retailer Vector cut power to hot-water cylinders for six hours on Monday and again last night but spokeswoman Philippa White said that was not extreme.

Rotorua had its coldest day since 1964 on Monday, but the lowest temperature recorded in the country was -10C at Tara Hills, near Omarama.

In Dunedin and Queenstown, temperatures plummeted to -6C, the icy roads catching an Australian visitor by surprise when his car skidded and landed upside down in Otago Harbour. He escaped unhurt.

Mr McDavitt said the coldest days usually came about six weeks after the winter solstice.

Although the winter solstice normally falls on June 21, this year it's tomorrow by a whisker, with the sun at its lowest northerly point in the sky at 26 minutes past midnight.

OUTLOOK: CHILLY

* Cold front expected to dump up to 15cm of snow over Southland, Canterbury and Otago.

* Alpine roads likely to be closed.

* Front reaches Cook Strait tonight, bringing icy-cold southerly gales, rain, hail and thunderstorms.

* Situation in South Island expected to improve tomorrow, bad weather in North Island may continue into the weekend.

* Winter has another 71 days to go.