During the last days of September, devastating frosts swept through larges stretches of Chile from Copiapo in the north, to Talca in the Maule valley, affecting an area of more than 900 km in length in Chile´s main fruit growing and wine production areas. Officials are saying that this is the worst episode of frost in more than 80 years. The Winery association ”Vinos de Chile” says it is doing everything it can together with the local authorities to alleviate the worrying situation affecting thousands of grape producers from north to south. Similarly, a task-force has been formed between the associations ”Cofradia del Vino”, the National Association of Enologists and the Chilean Wine Corporation (CCV) to analyse the situation and propose an action plan for the affected producers.
While initial reports suggest a 20% reduction in production for the 2014 harvest, the true situation however, will not be known until nearer November.
In the Casablanca Valley, approx. 40% of Chardonnay and Pinot Noir production has been affected. Temperatures during the last week have been down to an average of -6º C, with a peak low of -8ºC.
The first frosts began during the week of the 16th of September, the result of polar winds sweeping up from the Antarctic. Initially, areas towards the south were most affected, however in the latest frosts, the damage has been more widespread affecting not only grape producers, but also fruit growers. Producers of nectarines, cherries, pears, kiwis, walnuts, almonds, blueberries and table grapes are calculating their losses. The President of Fedefruta, Cristian Allendes, estimates that the damage to fruit production is between 10 – 70%, with financial loses of at least 1.000 million USD.
What happened? Why is this year’s frosts so damaging?
According to the Meteorological Institute of Chile, polar winds normally occur during July and August producing low temperatures in most of Chile. For the fruit growers, the occurrence of polar winds as late as the end of September caused a worrying situation. Early budding fruits and grape varieties, advanced with the onset of spring, had already lost their natural protection from the cold and were left vulnerable in temperatures below zero.
August marks the end of winter in Chile, and in September the annual growth cycle of the grape starts. As average daily temperature rise above 10 ºC, the pruned vines, warmed by the soils carry water and nutrition up from the root system and out through the pruning cuts. Tiny buds with a high water content start to swell on the vine. At “bud break”, the buds burst open with tiny shoots – the first sign of greenery in the vineyard. The more developed the bud, the less likely its capacity to withstand a freeze event. This is the most critical phase of the vine development. Extremely low temperatures frost can severely damage or kill emerging buds, which are the basis for the new shoots that will support the grape production for the coming years. Early budding varieties such as Chardonnay are particularly at risk from frost damage during bud-break.
What can be done to combat frost damage?
In areas prone to frost, vineyards can use a number of pruning techniques and mechanical techniques to prevent frost damage including small heaters placed around the vineyards, large tower air-circulators (similar to wind turbines), helicopters or a spray system that sprays water on the buds, enveloping them in a protective layer of ice. Unfortunately all of these techniques had limited affect last week since the cold air from the polar winds was so deep, there was no warmer air that could be drawn down and circulated to the vines.
A full report of each valley and the grape varieties most affected will follow in our next report. (Part 2)
Jane Nisbet Huseby, Chief Editor, Wine Source Chile