(Forbes) - It’s been estimated that the 6.0 magnitude earthquake that struck Northern California last month has caused over $1 billion in damages, some of which has bled out of oak casks onto the floors of Napa region wineries.

This represents a significant chunk of the annual revenue of Napa wineries, which generate about $13 billion a year for the regional economy. It also comes right at the start of harvest season on top of a tough year for weather as the region continues to battle one of the worst droughts in decades.

Mother Nature’s double-whammy raises some serious concerns about the wine economy in the U.S. and may even have a larger impact on the macroeconomic picture. Some of the stats may surprise you. For one, the U.S. wine industry is big. California wineries sold 214.6 million cases to U.S. consumers in 2013 (a total of $23.1 billion in retail sales), up 22% since 2003, according to stats compiled by the Wine Institute. That created an estimated $61.5 billion in state economic impact and $121.8 billion in national economic impact, with $14.7 billion paid in state and federal taxes.

To put that in perspective, annual revenues for the entire U.S. restaurant industry were just $659 billion in 2013.

I can attest to the surging interest in California wines based on my trip to Napa earlier this summer. I’m a big wine fan and try to get out to wine country whenever I pass through the area, so this wasn’t my first experience in the Mecca of the U.S. wine industry. It was, however, the most crowded.