Hoar frost in Central; temps drop to minus 10

It was promised and it was delivered - Central Otago woke to picture postcard-like hoar frost conditions this morning.

MetService meteorologist Tui McInnes said conditions had aligned to produce the phenomena.

"Overnight last night was basically the perfect set-up."

Hoar frosts occurred when air temperatures were below freezing and that, combined with any moisture in the air, led to that moisture freezing on to any surface it came into contact with, he said.

An overnight low of -7.7degC was recorded at the weather station at Alexandra Airport.

A view over Lake Dunstan from a hill near State Highway 8 above Clyde. Photo: Shannon Thomson
A view over Lake Dunstan from a hill near State Highway 8 above Clyde. Photo: Shannon Thomson
The elevation of the site meant the ground temperature in Alexandra itself and surrounding areas such as Clyde was likely to be lower, Mr McInnes said.

The Alexandra and Clyde area appeared to be the epicentre for cold conditions based on MetService recording stations, with the station between Omakau and Alexandra recording a low of -5.8degC overnight, while into the Teviot Valley conditions were relatively warmer with 0.2degC recorded in Roxburgh and -2.5degC in Millers Flat.

Meanwhile the mercury dropped to -10.9degC in Omarama this morning, with MetService forecasting a "high" of just 5degC today for the town today.

Resident Jim Harkin said there was a hoar frost on the trees and it was crunchy on the ground.

"We had that good dump of snow a couple of weeks ago and that's still on the golf course, so won't be playing golf on the golf course for maybe another week or couple of weeks."

That was not going to stop Harkin playing golf today at the Otematata course.

"It's 24km down the road and I'm hoping it's a bit better than here."

Harkin said the freezing weather can make the roads treacherous.

"You get a bit of moisture on the roads and it freezes it's definitely a bit tricky at times."

The icy conditions led to a double truck crash on State Highway 8 near Tekapo which closed the road for several hours.

 - additional reporting RNZ