Violent storms have hit Portugal’s Douro Valley, severely damaging vineyards and infrastructure.

As reported by the Drinks Business, Pinhão, a small town in the region, received three inches of rain and hail in just a few hours on Monday evening — almost double the typical average for the entire month of May.

The full extent of the storm’s destruction is still unknown, though grape growers are likely fearing the worst, with some local producers already estimating up to 80 percent losses from their worst-hit vineyards. In Pinhão, meanwhile, the flash flooding was significant enough to damage the town’s roads and terraces.

The Douro Valley is famed for its high-quality wines, as well as producing grapes for the nation’s emblematic fortified wine, Port.

Speaking to the Drinks Business, Adrian Bridge, managing director of historic Port shippers Fladgate Partnership, revealed that severe hailstorms “have been increasing each summer for the past few years” in the region.

It is but another indication of the increasing effect of global warming in winemaking regions worldwide, with the flash storms arriving just a few days after Bordeaux was also struck by devastating late-May hailstorms.