(Decanter) - A powerful earthquake that rocked winery buildings and threw barrels across cellars near Napa in California should act as a warning to producers, some winemakers believe. 

Many winery workers have been forced to juggle 2014 harvest commitments with clean-up operations following the 6.1 magnitude earthquake that struck in the early hours of Sunday morning and left close to 200 people in hospital, three with serious injuries.

Wineries were still assessing the damage by Wednesday morning. Initial reports varied from those who suffered ruptured tanks and saw barrels and bottles strewn across cellar floors to those who had very little damage at all.

But, there was emerging hope that, despite individual misfortune, not as much wine has been lost as was first feared.

'Some affected wineries may experience loss of inventory, [but] the earthquake will not have an impact on the overall supply of California wines,' said California's Wine Institute.

At Trefethen winery, where 'barrels were upended and debris from bottles, equipment and furnishings was spewn about property-wide', most of the 2012 and 2013 vintage wine survived unscathed.

'While there is no good time for an earthquake to hit, Mother Nature was kind to us in her timing nonetheless,' said Trefethen winery president Jon Ruel. 'This week is the small window when we are post-bottling and pre-crush.'

He added, 'While the large stainless tanks sustained some damage, some being sheared from their mounts, the wine was able to be moved to other tanks without loss.'