Were Grapevines Ready for Bomb Cyclone?

Frigid temperatures test even wine grape cultivars from Midwest to East Coast

by Linda Jones McKee
wine cold snow bomb cyclone
A National Oceanic and Atmospheric Administration satellite captures the "bomb cyclone" moving up the East Coast.

Lancaster, Pa.—Weather forecasters are predicting more severe cold weather today across the Upper Midwest, the East and into New England, with low temperatures dipping into negative numbers in many areas. It’s now been almost two weeks of unremitting bone-chilling weather in these regions.

With this long stretch of unusually cold temperatures, grapegrowers in the Upper Midwest and the East naturally wonder how their vines are doing. Had they acclimated to a deep freeze?

It’s been really, really cold
The current frigid weather pattern moved into the upper Midwest prior to Christmas weekend. By Boxing Day, single-digit nighttime temperatures were recorded across the East and into New England. Temperatures in Indianapolis, Ind., dropped to -12° F on Jan. 2, the coldest morning for that date since 1887. In Minneapolis, Minn., the temperature on New Year’s Eve dropped to -11° F.

In some places, the cold was accompanied by snowfall measured in feet, not inches. Erie, Pa., located at the center of the Lake Erie Grape Belt, had 121.3 inches of snow between Dec. 1 and New Year’s Eve, a record amount for one month. In 30 hours, including Christmas day, 53 inches of snow fell in Erie.

This week, a storm system that brought snow to Georgia and South Carolina moved up the Atlantic Coast. As it moved north, the storm became a “bomb cyclone,” a description used by weather forecasters when a low-pressure system undergoes bombogenesis, a rapid drop in atmospheric pressure of 24 millibars or more in 24 hours. Winter Storm Grayson (as the bomb cyclone was subsequently named) hit Long Island, N.Y., with more than a foot of snow, frigid temperatures, winds gusting to more than 60 mph, and unusually high tides.

Were the grapevines prepared?

Source: National Oceanic and Atmospheric Administration
Many of the grapes that grow in Minnesota are either hybrids or varieties specifically bred for cold-climate conditions. Dr. Matthew Clark, assistant professor of grape breeding and enology at the University of Minnesota, told Wines & Vines that the first frost in Minnesota was in mid-October.

“It got cold in November,” Clark said, “but it usually doesn’t get this cold until mid-January. So far, the lowest temperatures were -12° F or -15° F.” He noted that while many of Minnesota’s grapes are cold-climate varieties, this winter may be a test to see how well those grapes acclimated to early cold weather.

Snowfall along the shores of Lake Erie is often lake effect snow, in that it occurs when the lake has not yet frozen over. Bryan Hed, research technologist in plant pathology at Penn State University's Lake Erie Regional Grape Research and Extension Center in North East, Pa., said, “Temperatures have been dropping gradually, and I think the vines have had plenty of time to acclimate to the single-digit temps we’re getting now. What concerns me is the possibility of dropping below -5° F on Saturday (Jan. 6). When temps get below that, V. vinifera buds can begin to perish.”

Dr. Paolo Sabbatini, associate professor of horticulture at Michigan State University, said that he had just returned from a meeting with grapegrowers in southwest Michigan, where temperatures had dropped to -14° F. The growers were quite concerned, according to Sabbatini, but there’s nothing anyone can do about it, just wait and see what the rest of the winter brings.

According to Dr. Tim Martinson, senior extension associate at Cornell University, “Acclimation works best when it happens slowly,” as it did this past fall in the Finger Lakes. “As it gets colder, miraculously, (vines) get more hardy.” Martinson remembers the “Christmas Massacre” the Finger Lakes experienced in 1980, when temperatures on Christmas Eve day were above 32° F and then fell to -20° F overnight. While that event severely damaged many vineyards in New York, Martinson doesn’t think this current sustained period of cold weather will be devastating to the vines.

“I’d be more concerned if it warmed up to 50° F for four days,” he said.

Dr. Jim Meyers, extension specialist with Cornell Cooperative Extension in eastern New York, reported that the Champlain region had experienced some -20° F temperature events. “That’s not good,” he said, “but when you’re growing grapes that far north, most of the grapes are hybrids.” Meyers was more concerned about the -10° F temperatures in the Hudson Valley, where the Pinot Noir, Cabernet Franc, Riesling and other vinifera varieties are more at risk for bud damage.

“It’s too soon to tell,” Meyers commented. “We’ve been collecting Hudson Valley data for two to three weeks now and testing the buds, so we may get some indication of bud damage. This cold event was significant and carries some risk.”

Ron Wates, vineyard manager at Boordy Vineyards in Hydes, Md., told Wines & Vines that they had finished harvest by Oct. 18, which is somewhat early for the winery. “Most of the vines had shut down by then and were not actively producing growth,” he said. “We started pruning in mid-December because everything had hardened off.”

What concerns Wates is the “climate mood swings” that may occur over the remainder of the winter. It is, after all, only the first week of January.

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