Why we're dreading the 2014 frost season

Last week, we saw budbreak in our Grenache, Grenache Blanc and Viognier blocks.  This week, it's been joined by most of the other grapes, with only Roussanne and Mourvedre still fully dormant.  It won't be more than another week or two before they look like the Grenache below, photographed this morning:

Back in 2008, I wrote the blog post Budbreak is terrifying, but hopeful in which I talked about the combination of anticipation and fear that comes with the early beginning to a new growing season.  The anticipation should be obvious: it's the kickoff to the vintage, a time when the dormant vines spring to life and grow visibly day by day.  The fear comes because we rarely make it through April without some sort of a frost, and nighttime temperatures can drop below freezing as late as mid-May.

In an ideal world, we'd see frosty nights reguarly through mid-March, well interspersed with winter storms.  Sun between these storms is fine, as long as it drops below freezing a couple of times per week.  Then come the end of March, we'd see the season transition to sunny and mild, leading to budbreak some three weeks later and leaving us only a few weeks of high frost danger.  If it sounds like wishful thinking, it largely is, though what I outlined fits the pattern of the 2012 vintage pretty well.

If 2012 sits at one end of the spectrum -- I wrote about budbreak on April 17th -- this year sits at the other end.  This winter started off cold and dry but beginning in January we saw nearly two months of sun and warmth. Since January 1st we've only seen four nights drop below freezing, most recently the nights of February 4th and 5th, neither of which were frigid, dropping down only to 29 degrees.  Then, starting February 24th, we saw twelve consecutive days with lows bottoming out in the 40's and 50's, dropping only once in that stretch into the (high) 30's.  What does a month of non-freezing weather, capped by nearly two weeks of active warmth and ample sun tell the grapevines?  That spring has arrived, and it's time to get moving.

Looking back at the records I can find, this is the earliest we've been talking about budbreak.  Last year we reached the stage we're at now the first week of April.  2012 was late, as detailed above.  2011 saw budbreak the first week of April (and we got clobbered by consecutive nights in the low-20's the next week). 2010 was the last week of March. We should have been safe in 2009, with budbreak not until the second week of April, but we got hit hard by frosts April 25th and 26th. 2008 was the last week of March. 2007 was early April, delayed by our coldest winter on record.  So, in the last eight years, we're roughly ten days earlier than the next-earliest budbreak, and two and a half weeks earlier than average.

What do those two and a half weeks mean?  A very small chance of avoiding frost entirely, given that we've got two full months having to get lucky every night.  And a significantly increased risk of serious frost damage, given that we've got nearly six weeks when temperatures could drop into the mid-20's.

There are positive examples to look to, most notably 2010, which saw a late-March budbreak followed by six weeks of non-freezing weather.  But I think there is a greater chance of us seeing significant damage from frost than there is of us escaping unscathed.  And unlike in 2009 and 2011, when Roussanne and Mourvedre were still largely dormant at the time of our serious frosts, we're unlikely to have our most-planted and most important grapes dodge this year's bullet.

2014 was the first year we've ever bought crop insurance, spurred by the drought.  Though the drought still looms, our late-February/early March rain has mitigated those fears somewhat.  Now we turn our worries to two full months of frost risk.  Here's rooting for the insurance company.