(Dacanter) - Hail stones the size of walnuts peppered north California over the weekend, causing bewilderment and consternation among Napa Valley winemakers.

Freak hail storms struck the Napa Valley on Sunday 11 June.

Thunderstorms brought lightning, wind, rain and hail—as well as snow in the Sierras—and temperatures fell by as much as 25 degrees Fahrenheit. Some observers in the Bay Area reported hail stones the size of walnuts.

Such weather is distinctly unusual for this time of year and it caught many winemakers by surprise.

‘This was the most intense hailstorm we have seen in our 31 years on this property’, said Carole Meredith, of Lagier Meredith, who grows varieties including Zinfandel, Mondeuse and Syrah on Mount Veeder.

Lagier Meredith survived with only torn leaves, and no damage to fruit or shoots, but not everybody was so fortunate.