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GUNDERSHEIM, Germany — Europe’s iconic winemaking regions are reeling after extreme weather wreaked havoc on their crops.

However, there might be a silver lining. Some experts believe the surviving grapes will be of "extremely high quality," which should make for great wine.

The amount of grapes picked in France is expected to decline by 18 percent year-on-year following a spring frost wave, with authorities warning that the harvest will be the smallest in seven decades.

Across the border in Italy, a cold spring, a long hot summer, and sporadic hailstorms are expected to take an even bigger toll.

“Our initial estimate of a 25 percent fall in harvest is optimistic,” said Riccardo Cotarella, the president of Assoenologi, Italy’s main winemakers’ association. “If dry conditions persist and it doesn’t rain soon, it will be a lot worse.”

Cotarella warned the harvest could be down by as much as 60 percent in some regions.

Adolf Dahlem checks on vines damaged by a hailstorm in Gundersheim, Germany. Carlo Angerer / NBC News

German winemakers are also facing the possibility of an underwhelming year. The country’s farmers' association expects the harvest to be “below average,” although there are no concrete estimates yet.

That’s worrying news for Adolf Dahlem.

His family-run farm lies in Germany's Rheinhessen area, where the first vines were planted by the Romans about 2,000 years ago. A massive hailstorm last week destroyed the grapes on about 850 acres of land in the area.

"There are hardly any leaves left," Dahlem said, pointing at rows of badly damaged vines. "It felt like the end of the world. I knew there wouldn't be much left."

Workers have been struggling to harvest the damaged grapes in recent days. They hope to save at least some, but many have already turned brown and are dying off.

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Dahlem estimates that at least 50 percent of the harvest will be lost, but it will be another two weeks before he will know for sure. And if it rains before the grapes are picked, many will rot and he'll lose even more.

"When I was a kid, the harvest would take place in October. Now we usually harvest in early or mid-September."

Raul Diaz, a London-based wine buyer and expert, said Europe’s wine harvest is not very consistent year to year. But while winemakers are used to dealing with deviations in their crops, the problem this year has been more “extreme” than expected.

French agricultural authorities have predicted that country's harvest this year will be the smallest since the end of World War II.

“People are used to dealing with frost, they are used to dealing with heat waves, but not as extreme as that,” Diaz said. “The bad weather only needs to come during a certain period of time. If it is really, really cold when the vine is sensitive — even for just two days — everything will be destroyed.”

On the flip side, a very hot summer often results in quick ripening of the grapes, according to Diaz. In Italy, for example, the harvest started between 7 to 15 days earlier this year than in 2016.

“They have to pick because they can see the grapes are full of sugar, which is not good for wine," he said. "Overall, we want a long ripening season, so you can develop a proper concentration of sugar.”

Some experts predict the quality of the grapes, and consequently of the wine, could be higher than in previous years.

“The grapes that survive are of extremely high quality,” Diaz added. “It is a paradox, in a way, if you think about it. Lots of things occur in the end, but the remaining fruit is very high quality.”

But Cotarella warned against assuming that the quality of the European wines will automatically be better this year.

“It is true that grapes mature thanks to the heat, but it’s also true that a long drought causes stress to the plants,” Cotarella said. "The quality will probably increase in those vineyards where the plant was carefully irrigated, and grown on clay at low altitudes, like on valleys. But that’s only 10 percent of the overall vineyards in Italy. The other grapes and vineyards will likely suffer."

Grapepickers work at a vineyard at Port-Vendres, France, on Aug. 15. That was 15 days ahead of the previous year's harvest date. RAYMOND ROIG / AFP - Getty Images

It's also too early to say whether shrinking grape harvests across Europe will mean wine lovers will have to dig deeper into their pockets to enjoy a bottle.

“It’s best to wait until later in September to have a more clear idea of what the impact on prices might be,” said David Gleave, managing director of Liberty Wines, a premium importer and distributor in the U.K. “The harvest hasn't even started in some places.”

But the tough year has already started having an impact on some wine lovers.

According to Diaz, British consumers are already seeing a 50 pence (64 cents) increase for an average £5 ($6.40) bottle of wine. That's likely because of the speculation about this year’s harvest and reduced wine volumes, he said.

As for Dahlem, the German producer, the reality of this year's losses is starting to sink in, making him worry about the future of his centuries-old farm.

He believes that extreme weather has become more frequent.

Adolf Dahlem examines his damaged vines. Carolo Angerer / NBC News

"We have a constant rise in temperatures," Dahlem said. "When I was kid, the harvest would take place in October, now we usually harvest in early or mid-September."

Despite these hurdles, the 55-year-old still enjoys growing grapes. He hopes that his sons will one day take over the operation, but worries that climate change will bring unprecedented challenges.

"They will probably question at some point if this farm would be able to support a family in the future," Dahlem said.

Carlo Angerer reported from Gundersheim, Germany. Claudio Lavanga reported from Rome. Yuliya Talmazan reported from London.