I’ve had one too many ‘severe weather warnings’ this winter – at least three times in the past couple of months I’ve heard of ice, snow and other Arctic conditions coming my way, only to wake up to nothing more than a cool, crisp dawn.
Nevertheless, temperatures across Europe do seem to have taken a tumble in the last day or so (as predicted); I’ve even heard from a reliable source that there is snow on the ground in Crete, of all places. Bordeaux is also looking rather icy at present, and predicted temperatures for Wednesday night into Thursday morning are as low as -11ºC.
At this time of year cold snaps such as this – by which I mean not catastrophically low – have no influence on the forthcoming vintage; if anything they can be beneficial, killing off vineyard pests. With a large area of vines in Sauternes (18,000 vines altogether – reported here) recently falling prey to Flavorescence Dorée, a disease transmitted by leafhoppers (cicadelles), this is not an academic point. Leafhoppers over-winter as eggs (inserted into the veins or shoots of the plant) or as adults. I’m not certain what it would take to kill off the eggs when they are so protected, but the adults will be very susceptible to such low temperatures.
Happily it is far too early for the vines to suffer much damage at -11ºC; but such temperatures during spring, when the vines are covered in tender new buds, shoots and leaves, would be a disaster. Currently the vines are dormant, and thus prepared for such temperatures. Very low temperatures can damage and even kill the vines though, as was seen during the winter of 1956 (I’m told!). There’s a little way for the temperatures to go before things get that bad; currently the predicted low falls short of very notable winters, such as the -15.2ºC in 1954, -13.2ºC in 1963 and the record for Bordeaux (measured at Mérignac airport weather station), -16.4ºC in 1985. Strangely there is no mention of 1956 in this list of record breaking years – there I think the problem was prolonged cold rather than a single very low temperature but I’m certainly open to someone with better knowledge putting me straight on that one.