This winter, record-breaking storm in January notwithstanding, has been chilly and dry. The storm systems that have made their way to us outside of that one historic one have tended to be duds, dropping just a few tenths or hundredths of an inch of rain. The cause of this, according to meteorologists, has been the return of the Ridiculously Resilient Ridge of high pressure that was a regular occurrence in our 2012-2016 drought. This long-wave weather pattern is characterized by a powerful high pressure system that sets up in the north Pacific, diverting storms that would otherwise impact California into the Pacific Northwest. The net result has been a lot of very dry months this winter:
The main difference between this year's ridge and the one in our 2012-16 drought (particularly the one that characterized the 2013-14 and 2014-15 winters) is that this year's set up further west. A high pressure system set up over or just west of California leads to dry, warm weather. But this year's was far enough west to produce a recurring pattern in which storms rotating around the ridge tended to pass just east of California, pummeling the Rocky Mountains with snow, bringing arctic weather as far south as Texas, and producing dry but cold conditions in California. A look at the number of below-freezing days this winter shows that this was one of our frostier recent seasons, with 41 below-freezing readings at our weather station so far. This number ties for our most since 2012-13, and we still have nearly two months of potentially frosty nights to go:
As recently as week-before-last, we were chased inside during our blending trials by hail, and we had nighttime temperatures drop into the 20s the morning of March 16th. But the last few days have felt different. It's been a week since our last frost night. And after nearly a month where daytime highs didn't get out of the 60s, Saturday hit 76, Sunday hit 80, and Monday hit 77. So, I wasn't surprised to see a lot of budbreak when I got out into the vineyard this morning. Viognier was the most advanced:
Budbreak, as you probably guessed from the name, is the period when the grapevine buds swell and burst into leaf. It is the first marker in the growing cycle, a point when we can compare the current season to past years. Upcoming markers will include flowering, veraison, first harvest, and last harvest. And like harvest, budbreak doesn't happen for every grape simultaneously. Early grapes like Viognier, Grenache Blanc, Grenache, and Vermentino tend to go first, followed by Syrah, Marsanne, Tannat, and Picpoul, and finally, often three weeks or more after the earliest grapes sprouted, Roussanne, Counoise, and Mourvedre. This year, it seems like lots of the grapes are going at once. I saw sprouting in Viognier, Grenache, Syrah, and even Counoise (below):
Budbreak 2021 is happening at an average time, historically, and at almost exactly the same time as last year. We've had some extremes in recent years; we're a month later than our record-early 2016, but two weeks earlier than our latest-ever start to the season in 2012, when we saw 57 frost nights, 21 after February 1st. Here's our information for when we first recorded significant budbreak the last dozen years:
2020: Last week of March
2019: Second half of March
2018: Second half of March
2016: Very end of February
2015: Second week of March
2013: First week of April
2011: First week of April
2010: Last week of March
2009: Second week of April
2008: Last week of March
Note that it's pretty much impossible to assign a hard date for something like budbreak. After all, it's not a single vine we're talking about, it's a continuum across 125 acres of vineyard with eighteen different varieties. And even with the quick start, more than half the vineyard is still dormant. This Roussanne bud is indistinguishable from what it would have looked like in January:
Budbreak happens when it does largely due to increases in soil temperatures. Grapevines (and all deciduous plants) are waiting for the annual signals that it's safe to come out of dormancy and begin their growing season. The colder the temperatures and the more water in the soils, the longer the vines stay dormant. As winter rains ease, days lengthen, and the sun becomes more intense, those soils start to warm up, and the vines begin a race to reproduce. Evolutionarily, plants are trying to balance competing risks and benefits. Emerge too early, and they risk suffering damage to their reproductive prospects through frost. Sprout too late, and they might not have enough time to ripen their fruit, which is necessary so that animals eat it and distribute the seeds.
We worry about frost too. Before budbreak, the vines are safely dormant, and a freeze doesn't harm them. But once they sprout, the new growth is susceptible to frost damage. April frosts cost us roughly 40% of our production in both 2009 and 2011, and we don't feel truly safe until mid-May. So, we've still got more than a month to go before we can relax, and because of how evenly the vineyard appears to be coming out of dormancy, we're already likely past the point where we could safely withstand even a moderate frost.
We'll be trying to stay one step ahead of the new growth to keep our sheep in the vineyard as long as possible. Knowing budbreak was imminent, last week was their last pass through the Grenache block below. We may only have another week or so in the late-sprouting varieties, but we'll give as many blocks as possible one last graze:
You might think that earlier budbreak increases the risks of frost damage. And yes, all other things being equal, having fewer nights where you have to worry about temperatures dropping below freezing is better than having more. But if you look at the two most recent frost years (2009 and 2011) both of those saw budbreak in April. Is it possible that the same conditions that keep a vineyard dormant longer in the spring raise the risks of frost damage once they finally do sprout? I think so. California weather patterns tend to be long-wave patterns, where conditions are more likely to be similar to what they are now in two weeks than to have changed entirely. Of course, it's spring, which is the most unpredictable season here. We'll see.
Looking forward, we should be OK for this week, with warm, dry weather in the forecast. Next week it looks like it might be wet. It's often in the aftermath of spring storm systems that frost risk builds. So, while we would love more rain, we'll be on high alert after. Fingers crossed, please.
Meanwhile, we'll enjoy the rapid changes in the vineyard, and the hopefulness of new growth. It feels metaphorical this year. We've all spent the last year in various forms of dormancy, trying to keep sheltered and safe. With the hopefulness of declining Covid case rates in California, expanding supply of and access to vaccines, and good government support as businesses reopen, I feel like we're all coming out of hibernation. I have high hopes for this year. Please join me in welcoming the 2021 vintage.