April is the cruelest month, breeding
Lilacs out of the dead land, mixing
Memory and desire, stirring
Dull roots with spring rain.
– T.S. Eliot, The Waste Land (1922)
That dreaded Grim Reaper, the late spring frost, made an appearance again this year. The map above was produced by the National Aeronautic and Space Administration (NASA), and it tracks March temperatures around the globe. The areas shown in orange and red are indicative of temperatures well above the norm, illustrating that the planet is essentially “running a fever” over the last 29 years. Yet eastern North America appears blue, “shivering under a cold regime which seized control in January,” wrote Jason Samenow in The Washington Post on 16 April 2014, “The eastern United States: A lonely cold pocket on a feverish planet.” Mr Samenow notes,
The wave after wave of bitter cold that has walloped the eastern half of the U.S. since the start of 2014 has truly been an anomaly set against the temperature pattern around the rest of the world. Incredibly, the eastern U.S. is the only region of the world that has been colder than normal each of the first three months this calendar year.
What is going on here?
On 11 April 2014 the Virginia Wine Board Marketing Office issued an urgent notice advising of a threat of frost on April 16 and 17. A company called WxRisk.com is particularly skilled at weather modeling (note that they seem not to spend much time on their website while keeping things current on their WxRisk Facebook page). They provide detailed weather forecasting for businesses, commodity traders and investors.
- Southwest VA
- Shenandoah Valley
- Northern Piedmont
- All of Western and Central Maryland
- All of Central and Eastern West Virginia
- Western North Carolina Mountains
The air mass behind this front is quite cold and many areas Wednesday morning will see temperatures down into the middle 30s. Some temperature readings in Central and Eastern portions a West Virginia, Western Maryland, Southwest Virginia and the mountains of Western North Carolina will see temperatures drop into the middle and upper 20s. Wednesday night into Thursday morning will be even colder. Right now the data indicates much of the Shenandoah Valley as well as all of Central Maryland and the entire Southwest third of Virginia, Eastern half of West Virginia and the Western North Carolina mountains will drop to it least 28 degrees, if not lower.
A check (at the time) on Weather.com showed some disturbing numbers, especially for the Shenandoah Valley. Monday had nighttime lows in the low 60s, but by Tuesday lows were projected to be 24°F in Staunton, Raphine and Fishersville, and 28°F further north in Front Royal and Winchester. The Shenadoah Valley, incidentally, has 29 wineries, two cider producers, and one mead producer, according to virginiawine.org. There must be other vineyards, but information on them is not readily available. Wineries in the vicinity include Rockbridge Vineyard, Barren Ridge Vineyards, and Glen Manor Vineyards.
Factors like wind (or the lack of it) and individual area micro-climates will figure into whether or not a particular vineyard will suffer. One thing that distinguishes the valley are the flanking mountain ranges, the Blue Ridge Mountains on the east and the Allegheny Mountains to the west. The growing season can be distinctly warmer and drier than other parts of the Commonwealth because of the rain shadow created by these two mountain ranges. Winters, however, can be brutal, with heavy snowfall and winter vine kill, and that same topographic advantage turns deadly with the pooling of freezing air on the valley floor during events like this.
At first we were hopeful we’d avoid it, but the closer we got to the event the more dire the situation looked, because it is becoming clear that most of the region will be affected. South Central Virginia was looking at lows around 32°F or 33°F both days, and Charlottesville is expecting 30°F on Tuesday, 34°F on Wednesday. Asheville, North Carolina was faced with 26°F on Tuesday and 32°F on Wednesday, and Elkin, North Carolina in the Yadkin Valley American Viticultural Area (AVA) was looking at the same temperatures as Charlottesville. Further north, Frederick, Maryland was expected to reach 28°F on Tuesday and 31°F on Wednesday, and Middleburg in Northern Virginia was faced with 29°F on Tuesday and 32°F on Wednesday. All of West Virginia was no better.
Coincidentally, last Friday we had a meeting with a contractor and the structural, civil and electrical engineers we’ve retained to work on our tasting room and wine storage addition (more on that at a later date), who mentioned that a few years ago he was touring the vineyards at Biltmore in Asheville, North Carolina, and asked about their extensive sprinkler system in the vineyard — and this was after being told that their vines are dry-farmed. He was told that the sprinklers are for frost protection, and it looks like that system got a workout last week.
The results – and some soul searching.
The results? WxRisk circulated a follow-up report that showed temperatures were in the low- to mid-20s throughout Central Virginia, with dew points in the middle and upper 20s, which when combined with the wind was in a range that did not support the development of frost conditions in many areas. With bud break holding off because of the late start of the season, many vineyards — including ours — survived the event relatively unscathed.
What can we learn from this, in light of what we are learning about our changing climate? Climate scientists are coming to realize that there is a dipole force at work — the resilient ridge of air pressure over the Pacific that is being blamed for California’s drought has a an effect “downwind” causing the extreme cold affecting the East Coast by diverting the jet stream south.
A summary of a recent study put it this way: “The research provides evidence connecting the ampliﬁed wind patterns, consisting of a strong high pressure in the West and a deep low pressure in the East [labeled a 'dipole'], to global warming.” See “Bombshell: Study Ties Epic California Drought, ‘Frigid East” to Climate Change,” by Joe Romm in Climate Progress, 15 April 2014). The study concludes that these patterns are intensifying, which is not welcome news for either coast, although it is seen as a precursor to an E; Niño year, which typically brings increased rain to California, certainly a welcome development should it come to pass. Other scientists have noted that the melting of polar ice is the cause of the ridge over the Pacific — just Google “ridiculously resilient ridge” for a whole plethora of news reports.
Bear in mind this is computer modeling, albeit very sophisticated computer modeling, so a “grain of salt” is in order. But if this pattern is a “new normal,” then coping means most Eastern wine growers need to put serious thought to installing frost protection. The conventional wisdom among Virginia growers is to expect to be hit by frost and lose a crop to it once every seven years. Looking back, after losing a crop in 2012, and nearly doing so in 2014, and looking forward to the prospect of increasing and intensifying cold weather events like this one, it seems prudent to start pricing frost protection systems now in advance of the next growing season.