Some North Coast of California grape growers are calling this spring the frostiest in years, with scattered reports of close calls and some damage to vine shoots that had budded early.
The temperature around the North Coast dropped to around freezing on up to 13 nights in late March and early April, forcing growers to lose sleep as they wielded or readied frost-protection measures such as water sprinklers and wind machines for sometimes four or five nights in a row.
Early projections for how much frost damage will affect winegrape crop yield this season range from 5 to 10 percent. Yet the full extent won’t be known until grape clusters start forming and any secondary or tertiary vine growth appears after any frost-burned initial shoots die. Some growers fear production could fall by 25 percent in some vineyards.
Jeffrey Popick, a vintner in St. Helena who represents more than 100 North Coast growers for the Allied Grape Growers marketing group, told the North Coast Business Journal that he has seen and heard about frost damage in the Carneros appellation and in Suisun Valley of Solano County, locations where three- to four-inch Chardonnay shoots showed signs of burn.
Wild swings of cold and warm spells were courtesy of four cold-air and high-pressure systems from western Canada that were too dry to allow clouds to form a nighttime blanket. The lowest temperature reported in Sonoma County was 25 degrees, and it reached 27 degrees for three hours in Russian River Valley.
Charlie Barra of Redwood Valley Vineyards in northern Mendocino County said he used up a lot of the water in his storage ponds battling 15 nights of frost beginning March 16.
Running out of water is a real concern. In 1973, Napa Valley growers used up all their frost-protection water after a dozen straight days of frost and lost a large portion of the crop on the 13th night.
Here’s hoping this year’s crop yield is impacted only slightly.