NAPA -- April was a cruel month for California winemakers, bringing a series of unusually late frosts to vineyards bearing the tender, green shoots of spring.
The damage still is being assessed -- it could be June before growers know the full extent -- but most expect smaller-than-average harvests this year.
The toll could include parts of the San Joaquin Valley and, even more so, the Sierra Nevada foothills, according to the California Association of Winegrape Growers.
"It was cold in lots of places," said Karen Ross, the group's president. "There's lots of misery to be shared."
The cold snap's immediate effects can be seen in some vineyards, where leaves that normally would be fluttering pale green in spring breezes are curled up as brittle as December leaves.
The long-term consequences are less certain. Vines that survived the cold should produce normal fruit and quality shouldn't be affected, though growers might have to make some adjustments in how they maintain the vines, said Jim Regusci, president of Napa-based Regusci Vineyard Management. Even damaged vines might produce secondary buds that will yield fruit.
Still, the chances for a normal size harvest this fall are "probably pretty low," said Nick Frey, president of the Sonoma County Winegrape Commission. "Whether we'll be 2 percent or 10 percent (below average) is impossible to predict."
The frosts hit all over Northern California, including Mendocino and Lake counties in Northern California as well as the Napa Valley, Sonoma County and Central Valley regions. The cold also was felt in Central Coast vineyards.
Damage was spotty, a hallmark of frost, with some vineyards singed in only a few corners.
Sinking temperatures dragged growers out of bed as frost alarms on vineyard thermometers went off.
Although a little frost isn't unusual, this cold snap, which lasted 20 or more nights in some places, was a first for many vintners.
"The last one we had that was anywhere near this brutal was back in the '70s," said Napa County Agriculture Commissioner Dave Whitmer.
Farmers have a couple of options for fighting frost. Wind machines can keep low-settling cold air off vines and move in the warmer air. Irrigation also is used to deposit a thin layer of ice over buds, keeping them at about 32 degrees and preventing damage from colder temperatures.
Some vineyards didn't have irrigation protection because it's never been needed before. Others came close to depleting their water reservoirs, which could be a problem come summer.
"This frost, it's kind of the perfect weather pattern that came through just to blast us," Regusci said. "What happened was that it brought the temperatures down so low that it burned right through normal frost protection."
Fuel consumption was "unreal," he said, adding wryly, "Good timing, also, at four bucks a gallon."
Another unknown is what the frost might have done to next year's crop. Because vines are perennial, the area where buds for the 2009 harvest would form might have been damaged.
Predictions of a small harvest come after two years of relatively normal-sized crops had helped alleviate a grape glut, meaning growers were hoping to get good prices.
Regusci said there was no glut of high-quality cabernet sauvignon grapes, the type grown in the Napa Valley, so it's likely a smaller harvest means "the demand for good cabernet is going to go through the roof."
With the market moving back into balance, growers had hoped for a good year, Ross said.
"It's kind of like getting ready for that great banquet, and we thought this was the year the banquet was going to be extra flavorful," she said. "To have any crop taken away hurts."