Both Prince Edward County and the Niagara region were hit with unseasonably low temperatures over the weekend that sent farmers scrambling to prevent frost from killing their fruit.
They rented helicopters, turned on wind machines and set bales of hay aflame in the dead of night, hoping their rescue effort wasn't for naught.
The outcome was mixed: some smaller wineries say their crop was practically gutted in the deep-freeze, which tore through the region late Friday night and into Saturday morning.
"We knew frost was coming but nobody was prepared for what we got here," said Liz Dobson Lacey, sales manager at Lacey Estates in Prince Edward County.
"We still have another couple weeks (before we) see what the real damage is going to be."
At the Lacey Estates, the owners burned hay across their 3.5-hectares of land until sunrise on Saturday morning, but they could only prevent some frost damage.
In the lower fields, where cold air settles, all of the baco and chardonnay grapes were destroyed. Vines on higher land were mostly unscathed, with only about six per cent of the crops suffering damage, she said.
Other vineyards weren't so lucky.
Clark Tyler, manager at Harwood Estate Vineyards, estimates that a mere five per cent of grapes at the four-hectare vineyard survived the frost, and some of his friends lost nearly everything.
"It's difficult to wrap your head around," Tyler said.
"It has been a complete and utter shocker."
Farmers are counting on a stroke of luck, the chance of a secondary bud emerging on the damaged vines. If it survived the frost, the bud could save the crop, but there are no guarantees.
If the buds don't appear, the grape shortage could affect next year's wine selection.
Springtime frost is a persistent challenge for vineyards in southern Ontario, but this year the cold temperatures set a new precedent.
Environment Canada says its station in nearby Trenton logged the lowest temperatures on record for both May 22 (-0.3 C) and May 23 (-2 C) since it began monitoring the area in 1935.
"That in and of itself speaks to the relative rarity of getting temperatures this cold, this late into the month of May," said Geoff Coulson, a warning preparedness meteorologist for the national weather service.
Temperatures also dropped to record levels in the Niagara region where local growers also battled the frost.
A new low of -1.9 C was logged by Environment Canada on May 23, though the impact appeared to be less dire for growers in the area.
Vineland Estates winemaker Brian Schmidt bolted into action on Friday afternoon when his iPhone app sent him a frost warning. He rented a helicopter and took to the sky overnight in a fight to keep his crop alive.
Flying over the vineyard pushes warm air, and the heat of the helicopter's exhaust, down onto the grapevines, effectively raising the temperature above freezing. Meanwhile, his colleague drove across the land in a vehicle as he searched for the coldest spots.
"With the work we did with the helicopter we have no damage whatsoever," Schmidt said.
"You've got to get out and do something. If you don't, and you have damage, you're never going to forgive yourself."
Small family-owned wineries face the biggest challenge of deciding whether the financial impact of bad weather outweighs the expense of fighting it.
Wind turbines can cost around $40,000 each before factoring in the ongoing cost of fuel, and helicopter rentals aren't cheap either.
"It's a little tougher on the small guys," Dobson Lacey said.
For now, she plans to keep a close watch on her crop over the coming weeks. If she's lucky, the damage won't be as bad as it seems, but it's still too early to tell.
"This year was looking like a really great year," she said. "Then in less than six hours it was kind of taken away."
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