Heavy snow in New Zealand has closed roads, shut off power, and grounded flights across the nation as both the North and South Islands experience one of the heaviest storms in decades.

Snow is no stranger to New Zealand's South Island, but a blizzard reaching up to Auckland is almost unheard of. Both Wellington and Auckland saw their first snow storms in decades after an Antarctic blast moved north on Monday after lashing the South Island over the weekend.

The cold snap is expected to last until Wednesday and authorities are warning New Zealanders to be prepared.

Civil Defense Officer Rian van Schalkwyk warned:

"People need to make sure that they have all the amenities that they need, like warm clothing, proper food, and water."

Several schools, universities and courts closed in the lower South Island and across the nation on Monday. In quake-ravaged Christchurch, high winds and snow brought down power lines, cutting electricity to hundreds of homes and halting repair work.

Electricity was cut to thousands of homes in Wellington and north of Auckland as well.

MetService head forecaster Pete Kreft told the New Zealand Press Association:

"It's a once in many decades event. We are probably looking at something like - in terms of extent and severity - maybe 50 years."

The MetService recorded temperatures as low as -4 degrees Celsius (25 Fahrenheit) in Queenstown, the South Island's popular winter resort town.

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Many residents of the North Island took to the streets, welcoming the rare occurrence.

Veterinarians at the Wellington Zoo used the opportunity to allow Happy Feet, the lost emperor penguin they found starving on a Kapiti coast beach in June, a chance to enjoy the ice.

Prime Minister John Key even opened a press conference by welcoming reporters to the "winter wonderland that is Wellington."

"I can't personally recall seeing snow in downtown Wellington. My wife tells me there is snow around our house, or at least there was for a short period of time in Auckland, so it's very unusual," Key added.

Though Auckland received its heaviest snowfall in decades, much of it was washed away by the heavy rain that followed the snow. Four people in the city were taken to the hospital after heavy winds caused a tree to crash into their home.

As of early Tuesday morning, TV3 News reported that Queenstown was cut off from the rest of the country with a number of weekend visitors trapped there.

Both Christchurch and Queenstown airports were closed, though Christchurch Airport promised an update at 9a.m. local time.

Many state highways and all mountain passes across the Southern Alps in the South Island remained closed on Tuesday as well.

See raw footage of the storm below:

Storm Storm