Nelson pilots join the fight against frost

Nelson helicopter pilots made a mass exodus to Marlborough last night to join a squadron of frost fighters on standby to protect the region's vineyards.

Nine Nelson-based companies contacted on Friday morning had 15 helicopters on standby in Marlborough, with one also on standby for a Nelson vineyard, as overnight temperatures fell to near-record lows for November.

Although most of the helicopters weren't required to fly on Friday morning, Nelson pilots are expecting to be on standby again on Saturday and possibly Sunday.

"We had all three of our helicopters over there last night," Nelson Helicopters owner and chief executive Jeanette Lusty said Friday morning. "There's talk of being on standby for the next two or three nights."

Coast to Coast Helicopters also sent all three of its helicopters to Marlborough on Thursday. Owner-operator Andy Brown said they would "certainly" be back Friday night.

Toby Reid of Reid Heslop Helicopters said it had both its helicopters on standby in Marlborough but they weren't required to fly Friday morning.

"We weren't needed this morning but it looks like tonight's going to be colder. There's a big high moving across, so we might be flying tomorrow."

Vineyards across the Nelson region appeared to have escaped unscathed again on Friday morning, with only light frosts in most areas. A light breeze and cloud cover prevented a severe frost on Thursday after snow fell on the Barnicoat Range and the hills behind Nelson city on Wednesday night.

"I was up a couple of times during the night and I don't think it was too bad," Herman Seifried of Waimea Plains vineyard and winery Seifried Estate said Friday morning. "The temperature was around 1 to 1.5 degrees, with zero in one place, but there was a slight wind movement, which helped."

Helicopters were also on standby at vineyards in Otago, Canterbury and Hawke's Bay, which have young fruit and vines vulnerable to frost damage.

"There are 670 helicopters in New Zealand and 85-90 percent of them will be out on a big frost night," Helipro business manager John Read said. "I would not be surprised if there were more than 500 flying tonight, based on the forecasts I have seen."

Helicopters prevent frost damage by circulating the layer of warm air trapped above the freezing conditions closer to the ground.

Nelson weather forecaster John Mathieson said a minimum air temperature of 1.9degC was recorded in Stoke Friday morning, well below the mean November minimum of 9.8degC.

Thursday's maximum of 14degC was the third-lowest November maximum for over 20 years, he said, with the record low of 13.7degC recorded "near 1941".

However, Mr Mathieson predicted that the weather would warm up over the weekend.

Frosts were forecast again for Saturday morning, although they would be "the last throw of the dice for the current cold spell".

- © Fairfax NZ News