Of all the risks that we farmers have to face, frost and hail are the two most terrible and unjust. In the space of a few minutes, they can wipe out the work of a whole year, or even several years. However, by some kind of miracle or special privilege, the great terroirs very often escape these dreaded misfortunes. Hail is virtually unknown at Château Margaux. Why this is so, we do not know. On the other hand, we are spared frosts in most of our vineyard, thanks to its close proximity to the river, whose thermal inertia protects its surroundings from cold weather, and its height, which keeps the vines away from the masses of freezing air, which accumulate below. This protection is historically effective against winter frosts, which need temperatures of below -18°C (0°F). to cause damage. However, the vineyard can be caught by spring frosts, which were exceptionally severe in years like 1945, 1961 and 1991.

To every rule, though, there are exceptions. Our plot of white grapes is so prone to spring frosts that we decided in 1983 to install a system to fight off frost. The principle is simple: by spraying the vines with water for as long as the frost lasts, which is generally until dawn, the heat generated by the formation of ice enables the temperature to remain above the limit under which the vegetation is destroyed (from below -2.5°C to -1.6°C (20°F to 24°F), depending on the growing stage). The system is easy to set up; it is simply a question of switching on the pumps. However, man's rôle is not restricted to this simple act. It is also very important to decide if it is appropriate and, if so, to choose the right moment to switch on the sprays. Temperature, wind, air humidity must all be taken into account -and at three o'clock in the morning! When the decision has been taken, and this may happen two or three nights in a row, the inevitable feeling of tiredness is replaced by a great sense of relief, firstly to have saved the harvest and then consolation, watching the magical show given by the ice forming around the vine buds to make tiny, protective igloos.