hey saw it coming, and they still couldn’t stop it. Severe frosts in March, April and May punctuated one of the driest, coldest springs in history for Mendocino County, and winegrowers in many cases were helpless to save the tender new buds on their vines.

With each new threat to their vineyards, growers turned on overhead irrigation sprinklers to raise the humidity of the air or coated tender buds in insulating ice that holds steady at a safe 32º. “We survived, but I had to run my sprinklers more nights this year than in the previous eight years I’ve owned the vineyard,” said Larry Londer of Londer Vineyards.

Most growers were not so lucky.

“We had already used most of the water in our pond for frost protection early in the spring,” says Milla Handley of Handley Cellars. “By late April we ran out, and we had to start making decisions that break your heart.” Such as on the nights of April 21-22 and May 3, when temperatures in Mendocino County plunged into the twenties.

Ultimately Handley had to leave her Gewurztraminer vines to the merciless cold and save other varieties as best she could by pulling water from wells and dragging mobile heaters through the vineyard on a trailer. “We got hit hard,” she says, “but I’m hearing about a lot of places where it was even worse.”

Talk About Widespread Damage – Check This:

“Virtually every vineyard you walk into in Mendocino County shows damage,” says Glenn McGourty, the UC Davis extension viticultural advisor for the county. “Some places it’s fairly minor, and some places it’s 100 percent.”

Similar damage to vineyards has been reported all over the state, including in the Sierra Foothills and Central Coast. Pear, apple and walnut crops have been hurt as well.

Mendocino County agricultural commissioner Dave Bengston cautions that it’s still too early to assess total damage to the county’s winegrape crop. Yet his actions suggest he’s got a pretty good idea. He’s already started the state and federal wheels turning to generate disaster relief – financial assistance that usually requires a “one-third” impact.

“Anytime an event affects a third of the growers, a third of the acreage, or a third of the crop, it’s a disaster,” he explains. For Mendocino’s $90 million wine grape crop, this would mean a loss of $30 million in revenue. “I’ve already reported an impact more significant than that to the county’s board of supervisors,” Bengston says.

Q: How did it get so bad?
A: The answer lies partly with the weather, and partly with terrain.

The unrelenting cold was compounded by unseasonably dry weather in late winter and early spring. Instead of delivering replenishing rains, the skies remained clear and dry, day in and day out. March and April both set records for low rainfall in the north coast.

This combination created two problems. Either vintners lacked the water needed to keep their frost protection ponds full, or they had water but were unable to determine when to turn their sprinklers on.

“Everything has gotten so dry that the dew point falls below where people are used to,” McGourty notes. “If you start your sprinklers at the usual time, when the temperature is still a couple of degrees above freezing, it’s too late. You could actually accelerate the cooling instead of forestalling it.”

Potter Valley, a region with abundant water from Lake Pillsbury, saw temperatures in the low twenties on successive nights more than once, and anyone who didn’t turn on their sprinklers early could never catch up. Redwood Valley growers who relied on their water utility companies couldn’t get enough water fast enough no matter when they started.

But it wasn’t only the weather.

One of Mendocino’s greatest assets as a wine-growing region turned out to harbor a hidden trap. The county is made up almost entirely of hills and low mountains. Vineyards on hillsides and ridge tops deliver great grapes, and are generally considered immune to frost because cold air, like water, flows downhill. So a majority of new vineyards in the county have been planted high and dry in recent years - without frost protection.

In 2008, owners of these new plantings woke up to devastation on a scale they had never imagined - or been led to expect.

“Normally in Mendocino, the cold air pools between the ridges,” explains McGourty. “But we had a series of advective frosts, which means a mass of cold air sweeps in from the north that’s too big for the valleys to hold. It stratifies at high elevations. People up on the hillsides didn’t even have frost protection in most cases, so they were helpless.”

Bob Blue, the long-time winemaker at Bonterra Vineyards, just shook his head when I asked him in early May about bud loss from frost damage at Butler Ranch, a large, relatively young vineyard high above Ukiah Valley. “Massive,” he said finally. “Unbelievable. We’re still reeling, frankly.”

Eaglepoint Ranch, another large, high-elevation vineyard across Ukiah valley, sustained its worst frost damage in 30 harvests. Vineyard manager Casey Hartlip reports losing up to 70 percent of the green tissue on his vines. “We don’t have enough water up here to spray for frost protection, so we’re used to weathering some cold,” he notes. “But this was one of those winters that you can’t prepare for.”

Successive nights with lows of 27º in late April constituted the final hammer at Eaglepoint. “Some of the vineyard looks bad,” Hartlip concludes, “and the rest looks really bad. It’s just a huge loss.”

Long-Term Effects Still Unknown

Nearly everyone I talked to for this story insists that it’s too soon to say what effect the spring frosts will have on the winegrape crop or its quality. Grapevines naturally reserve a few “secondary” buds to push out in case their primary buds are damaged. The vines may also put more energy into their surviving clusters, producing enough extra fruit to at least partly offset their smaller numbers.

These effects – if they materialize - will be more meaningful to Mendocino growers than ever. “The last time the county was hit this hard by frost, in the early 1970s, the winegrape industry in the county was tiny,” Bengston points out. “This time, there are tens of millions of dollars riding on every crop.”

The impact may go well beyond the size of this year’s crop, however. Many growers are already nervously counting the number of weeks their vines are behind in normal maturation. “Due to the weather and the frost damage, we’re going to have a very late bloom and fruit-set, which means a late harvest,” Hartlip says of Eaglepoint Ranch. “That pushes us up against the possibilities of cold and wet weather in the fall. We pretty much need everything to break right for the rest of the season or it could get ugly.”

He could be speaking for the whole county. And that’s just this year.

Grapevines can be traumatized by a number of factors, including super-abundant harvests that exhaust their energies in subsequent vintages. Severe frost can have the same effect, which would reduce the crop size in 2009 after an already disastrous harvest in 2008. Finally, another frosty winter could retard the development of new hillside vineyards – something that Mendocino County has banked on to build its reputation as a world-class wine region.

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Photo of grape damage comparison courtesy of California Farm Bureau Federation, www.cfbf.com