Frost Damage and Recovery
April 25, 2011
We're two weeks removed from the frosts of April 7-9, which look like they'll play a major role in defining the 2011 vintage. With temperatures down to 24 degrees on consecutive nights, we sustained near 100% damage in the Grenache, Grenache Blanc, Viognier and Marsanne (the four earliest-sprouting grape varieties). It was so cold that even the tops of the hills froze, which hasn't happened in the twenty years we've been here. The cold temperatures in the upper and middle atmosphere meant that our fans were largely ineffective; we were moving out cold air but replacing it with air that was only slightly warmer and still below freezing.
We were far from alone; vineyards up at 2000 feet elevation saw similar levels of damage, as did those on the plateau east of town. It was only the vineyards with ample water supplies who frost protected with overhead sprinklers that (mostly) escaped.
The impact of the frost on the Paso Robles area was driven home to me by a trip I took last week down to Santa Barbara. Coming back through the Santa Ynez and Santa Maria valleys, we drove through vineyard after vineyard with six or more inches of growth. Returning to Paso Robles felt like moving from spring back to winter, as the Zinfandel vines that line US-101 in Paso Robles looked still fully dormant.
And there are still vineyard blocks at Tablas that are only just sprouted, like the Mourvedre block (left) and the Roussanne block (right):
The one vineyard block that had sprouted that didn't see extensive damage was the Chardonnay block that we protect with sprinklers. Here we saw limited damage (where the sprinklers became clogged or didn't reach) but most of the vineyard was protected:
The four most affected varieties account for about 35% of our planted acreage. And these vines will have to re-sprout. Grapevines are prepared, evolutionarily, for freezes, and have secondary buds that push only if the primary buds are damaged or destroyed. The photo below, from a Grenache vine, shows clearly the damaged buds (on the cane in the foreground) and the secondary buds pushing elsewhere:
Of course, these secondary buds are not always in the places you'd prefer, and it means a summer for Neil, Ryan, David and the vineyard crew of carefully selecting which canes are allowed to grow and which will inhibit the air flow around the vines and have to be removed. On the positive side, all of the rain that we received last winter means that the vines grow vigorously, and should have enough energy to spare to still produce decently off the secondary buds.
Still, it's depressing wandering around the frost-damaged blocks, most still with their withered leaves more visible than the new green growth. Another couple of Grenache vines illustrate:
With the early-sprouting varieties forced to start later by the freeze and the later-sprouting varieties just coming out now for their primary growth, it looks like it will be a busy October. There is every reason to expect that harvest will be late and compressed, with varieties that normally ripen weeks or months apart coming in at roughly the same time.
Production looks like it will be affected. The two years we've seen serious frosts (2001 and 2009) we estimate that we lost something like 40% of our production off of the affected blocks. But both of those frosts were later, and all the varieties had sprouted. It appears that the cool spring delayed budbreak sufficiently that our later-sprouting varieties like Mourvedre, Roussanne, Picpoul and Counoise (as well as, for some reason, Syrah, which wasn't much sprouted at the time of the frosts) didn't sustain much if any damage. So, I'd estimate that we're down perhaps 20% from what we might otherwise have been able to produce. Of course, the rest of the year matters. If we were to get another frost in the next few weeks -- and we estimate that we're still at risk of frost until mid-May -- the impact would be devastating. But if we're able to come through the frost season OK the ample groundwater should allow the vines a healthy ripening cycle.
Quality should be fine, if 2009 is any indication. The 2009 reds, which are just being bottled now, are some of the most compelling that we've ever produced. And it's good that the varieties on which we base our signature blends were the least affected. We'll know more, of course, by harvest time.
In the vineyard now we're furiously trying to get the cover crop mowed, disked and spaded into the soil. We're behind here as well because of how wet the spring was; it's only in the last three weeks or so it's been dry enough to get tractors into the vineyard. The weather has been cooperating, with days in the 70s and mostly dry. It's supposed to warm up further this week. Fingers crossed, please, everyone.