Polar blast sweeps country
Wintry shock won’t linger — settled weather on its way 19.4m monster recorded
Awintry weekend that brought a taste of Antarctica to New Zealand, closing roads and plunging temperatures below zero, will give way to more settled weather this week.
The polar blast that moved up the country proved the culmination of a complex system that pulled cold air up from Antarctica and dropped it across the country, pushing the mercury down to -6.5C at Waiouru and -5.7C at Mt Cook overnight on Saturday.
MetService forecaster Tom Adams said the sequence began with a low pressure system that rolled in from the Tasman Sea last Wednesday, before it unwound into an open trough that swept over New Zealand late last week.
When the trough, together with a tongue of warm air, blew through, it left a southerly flow of cold air.
“And embedded in that have been various cold fronts, the most significant of which was the one that crossed the South Island on Friday afternoon and evening, and then the North Island on Saturday morning and Sunday afternoon — this is what dropped the snow.” A 19.4m wave has been detected south of New Zealand — and the company that recorded the behemoth believes monsters reaching over 20m were probably created by the same storm.
Working with the Defence Force, science-based consultancy MetOcean Solutions recently moored a high-tech instrument in the Southern Ocean off Campbell Island, nearly halfway between the South Island and Antarctica.
Persistent westerly winds and an unlimited area for waves to build help make Southern Ocean waves among the biggest in the world.
MetOcean said the 19.4m wave was close to the highest ever recorded, which was detected rolling through the North Atlantic Ocean between Iceland and Britain last year.
It’s expected the buoy may ultimately register 25m waves — the
The dumping forced the closure of SH87 and SH1 north of Dunedin, and when the snow-bearing front reached the North Island later in the day, there was enough to close the Desert Rd and leave a dusting on the hills from Wellington to the Bay of Plenty.
On the Desert Rd, a snow plough and other contractors were brought in to clear the road and allow trapped trucks and cars to get through.
The snow delayed flights, coated height of an eight-storey building — as it continues its real-time readings fixed in 150m of water. But MetOcean senior oceanographer Dr Tom Durrant was nonetheless thrilled with Saturday’s wave, saying it was one of the largest recorded in the Southern Hemisphere.
“This is the world’s southernmost wave buoy moored in the open ocean, and we are excited to put it to the test in large seas.”
MetOcean managing director Peter McComb said waves larger than 20m likely also occurred between sampling times, which were for 20 minutes every three hours.
Improved observations would enable better forecasting and design of vessels for the Southern Ocean.
The Southern Ocean Wave Buoy data is freely available from MetOcean Solutions and can be seen at metocean.co.nz. — Jamie Morton farmland and treacherous.
But the wild weather was a promising sight for skiers with snow falling on Mt Ruapehu for the first time this year as well as further south at Coronet Peak and on The Remarkables.
If all goes to plan, Whakapapa ski field will open on June 10 and Turoa on July 1.
The snow fell from a cold front, which was followed by strong south- made driving