The powerful storm knocked trees down on some vines at Alfaro Family Vineyards in the Santa Cruz Mountains.

San Rafael, Calif. -- Record October rainfall soaked Northern and Central California vineyards Tuesday, prompting worry that many grapes still awaiting harvest would fall prey to Botrytis and similar ills. Wines & Vines spoke with sources from Mendocino to Temecula and learned that, so far at least, these fears were unfounded.

North Coast
Jennifer Putnam, executive director of the Napa Valley Grapegrowers, napagrowers.org estimated that between 60% and 70% of winegrapes in the area had been picked prior to Tuesday’s storm. She stressed, however, that harvest levels varied largely by location. Of the crop still hanging, the majority was Napa Valley’s flagship variety, Cabernet Sauvignon.

“Cabernet has thicker skin and slightly looser bunches,” Putnam said, indicating the variety’s physiology makes it more resistant to rot and fungal diseases. Aside from this week’s rain showers, the Napa Valley had experienced a “pretty optimum growing season,” which Putnam characterized as “a little bit late, but nice and even” -- free of heat spikes and June storms.

She added that many Napa growers were pleasantly surprised when the rains weren’t as heavy as expected. Meteorologists had predicted Napa would get anywhere from 4 to 9 inches of rainfall, Putnam told Wines & Vines, but “a lot of people saw about 3 inches.” In preparation for the forecast downpour, many growers whose Brix levels were within a reasonable picking range worked quickly to bring fruit in Sunday and Monday, before rainfall began.

By this morning, conditions were partly sunny in Napa, but the ground was still damp. “We’re supposed to see upper-70°s through the weekend; so it looks promising that people can get back in there within a couple of days,” Putnam said.

After a cool growing season nearly ideal for photosynthesis, harvest halted this week in Sonoma County, where light precipitation continued to fall this morning. Sonoma County Winegrape Commission president Nick Frey said winegrowers in his region typically finish harvest around mid-October, but heavy rains earlier this week have delayed the schedule by four or five days.

Still, he reported that area growers are nearing the finish line. Frey said that when the SCWC executive committee met Tuesday night, members detailed the status of their respective harvests: Grapegrowers in the county are about 85%-90% finished with picking, he concluded.

The rain is “going to affect a few people,” Frey said, adding that some Chardonnay and Zinfandel is still hanging, and those two varieties are susceptible to bunch rot. Presuming the sun shines Friday and through the weekend, Frey expected harvest to wrap up in about two weeks.

Mendocino County agriculture commissioner Tony Linegar said that growers on Sunday and Monday ordered “a flurry of picking” before the predicted downpour in the North Coast. “The wineries were just packed with fruit coming in.”

At this point, he guessed, about 20% (maybe 10,000 tons) of the crop in Mendocino County was still hanging. However, half of that may never be picked, because it hasn’t been sold to winery buyers. “It’s a tough year for selling grapes,” Linegar said, adding that varieties still on the vine include Cabernet, Merlot and Zinfandel.

For the crop that growers do still intend to harvest, high humidity during the past three days has raised concerns about Botrytis bunch rot, and the ground is not yet dry enough to support harvest efforts.

“We may see people rush out and try to get some fruit off (the vines) this weekend or tomorrow, if they can get into the vineyards,” Linegar said. “Some of the lowlands are going to be harder to get into.”

At this point in the season, there is nothing growers can spray to combat fungus, so vineyard owners with fruit still on the vines have little recourse but to cross their fingers. Meanwhile, the National Weather Service today called for mostly sunny skies and a high of 80°F in Ukiah on Friday.

Central Coast
The Santa Cruz Mountains AVA, where wildfires ravaged the steep hillsides the past two summers, received as much as 8 inches of rain in less than a day, accompanied by wind gusts up to 50mph. Shannon Flynn, operations manager for the Santa Cruz Mountains Winegrowers Association, said she’d communicated with association members via phone and Facebook throughout the deluge; during one exchange, a vintner reported that “trees were falling on his vineyards.”

Happily, Flynn said, most of the area’s Chardonnay, Pinot and Zinfandel had been picked prior to the storm. “What’s still out there is Cabernet, and it’s a hardy grape, as are Merlot and Syrah,” she reported. The storm blew by quickly, and by Wednesday, “It was almost hot.” Today, she said, “I talked to the winemaker at Woodside Vineyards, who was picking his Cabernet and had a nice breeze coming through to dry out the fruit.”

In neighboring Monterey County, Rhonda Motil, executive director of the Monterey County Growers and Vintners Association, commented, “A lot of guys were really busy before the storm. Normally, we only get 8-9 inches total rain per year: We got at least a quarter of that Tuesday.” Unlike the Santa Cruz Mountains, Monterey was at times inconvenienced by electrical outages.

Jason Smith, the association’s grapegrowing chair and general manager of Paraiso Vineyards, had worried that Botrytis or other rots would take advantage of the rain and humid, 80°F conditions that followed Wednesday.

“I think as far physical damage, right now we don’t see it,” he said. But he’s continuing to monitor closely, and noted that some grapes showed troubling color chan ges in one vineyard where there had been no signs of Botrytis on Wednesday.

With adequate advance warning, his team had harvested some 3,500 tons in three days prior to the storm. “We harvested 20 loads last night: 200 tons,” Smith said. Despite the unplanned rush to crush, he said, “The quality is great,” and the pace of harvest had been dictated by overcrowding in winery tanks. He estimated that about 60% of Paraiso’s 3,000 acres had been harvested before Tuesday.

Further south, in San Luis Obispo County, Becky Gray, executive director of the San Luis Obispo Vintners Association, said that after 5-7 inches of rain on Tuesday, “It’s supposed to be in the 80°s today, and back to normal by the weekend.”

Vineyard manager George Donati of Pacific Vineyard Co. in southern SLO County reported that he’d harvested 75-80% of his 2,000 acres prior to the storm. “Today it’s sunny,” he said, “and we’ll be picking tomorrow.” He hopes to finish his harvest in the next week or so. Yesterday, he said, “We turned on all our wind machines in low lying areas, about a dozen of them,” to help dry the grapes.

Next door, Santa Barbara County took a lesser hit, according to Jim Fiolek, executive director of the Santa Barbara County Vintners Association. “Rainfall was as diverse as the plantings here,” he said, ranging from 1 to 3 inches.

Fiolek pointed out that, due to the county’s position at the “elbow” of California, its major winegrowing valleys have an east to west orientation, perpendicular to other valleys on the Pacific Coast, and Pacific storms blow against the southern-facing mountains, which pick up most of the moisture.

“At this point,” he said, “the vineyard managers I’ve spoken with have not seen any green mold, bunch rot or burst berries.” And, fortunately for most, 75% of the county’s vineyard acreage is planted to earlier-ripening varieties and 95% of harvest was in before the rains came.

In the eastern end of the Santa Ynez and Santa Rita valleys, hardier but later maturing Bordelais varieties are still on the vine, but Fiolek reported that the weather in these warmer inland areas has climbed back into the 90°s and is expected to remain there for the immediate future. “If we get this for a week, it should equalize the sugars,” he said hopefully.

At the southern end of the state, Temecula could have used the rain, said Peggy Evans, executive director of the Temecula Valley Winegrowers Association. Thanks to a heat spike in September that forced some growers to turn on the irrigation, “We were pretty much done with our harvest,” she said. “I think for some varieties we were a bit light. It was not a big harvest, which was good; not an overabundance, which was good, but enough for everybody’s needs. We weathered the storm that didn’t come.”

Chilly in Washington
The unseasonable damp of California was paralleled by early freezes in other climes. Last weekend, temperatures in Eastern and Central Washington abruptly plunged to 20°F and below, and wineries like Latah Creek in Spokane Valley made the decision to accelerate harvest. “We got done yesterday,” said owner Mike Conway. “We had 50% of our production in last week, about half of our 17,000 cases” from his vineyard sources in Yakima Valley and Wahluke Slope.

This was about two weeks ahead of last year, Conway said, but he had planned to harvest these final grapes this week anyway. The premature frost, however, had Conway and other vintners scrambling for labor and trucking. “It appears we’ve got another record crop,” he said. “I get e-mails daily from vineyards with grapes available.”