(USAToday) - Near the height of annual harvesting and tourist season, California's Napa Valley wineries were struck hard by Sunday's magnitude-6.0 earthquake, but many reported surprisingly light damage.

The early morning earthquake, whose epicenter was about 9 miles south of Napa, jolted residents and had winemakers scrambling to check their homes and businesses.

"It was a very violent awakening," says Sandy Taylor, co-founder of the Taylor Family Winery in Napa. "It seemed to shake a long time. Our dogs and cats bailed out."

Taylor says her winery, about a mile from the epicenter, lost one barrel of 2013 Chardonnay. "The finished bottles at the winery were fine, Taylor says. "The finished goods are in cases, boxed, palletized and shrink-wrapped," she says. "I think the shrink-wrap was what kept them safe."

At Silver Oak winery, about half a mile from the epicenter, three barrels were destroyed, CEO David Duncan says. The biggest loss was the winery's "reference bottles" – bottles of wine used to blend previous vintages. "They're completely irreplaceable," Duncan says.

Nevertheless, the winery's tasting room was open Sunday, running on generator power. A water main had to be repaired in the early morning.

Napa is home to nearly 800 wineries, which produced 49.7 million cases of wine in 2012, according to the Napa Valley Vintners, a trade association. The association puts the industry's U.S. economic impact at $50 billion, and an overall estimate of the damage from the quake couldn't be assessed Sunday.