Hail: Does Burgundy have the ultimate weapon?

Anti-hail generator installed at Volnay , in Côte de Beaune .

Burgundy and the Beaujolais Do they possess the ultimate weapon against hail, as the recent storms might suggest? While everywhere else (Touraine, Bordeaux, Cognac, Languedoc…) the devastation is measured in thousands of hectares, the region is faring relatively better than others… for now. The Mâconnais is , a priori, the most affected wine-growing region to date, at Vergisson , Solutré, Mancey, Pierreclos, Prissé, Lugny… and around village of Chapaize, where dozens of hectares have been destroyed. The north of the Côte de Nuits also suffered between Gevrey-Chambertin and the south of Marsannay In these different sectors, the damage varies considerably, ranging from 10 to 50% of the expected crop loss. Gevrey suffered a double blow last Tuesday evening with torrential rains; over 100 mm fell in one hour, flooding cellars, eroding hillsides, and carving deep trenches between the rows. Any intervention using a straddle tractor is currently complicated and dangerous, even though copper treatments should be applied quickly to promote healing of wounds on the leaves and grapes. ODG of the villages of Gevrey-Chambertin and Brochon They have also officially requested permission to carry out treatments by helicopter, which is currently prohibited except by ministerial exemption; the file is on the desk of the prefect of Côte-d'Or, whose response is expected today. Beaujolais which had until then been relatively spared, was hit yesterday and in villages Like Blacé or Dénicé, the damage is significant.

A generator to protect Airbus aircraft from hail

Burgundy and the Beaujolais They were not spared, but Thiébault Huber, a winemaker in Meursault , president of the CAVB (Confederation of Appellations and Winegrowers of Burgundy) and of ARELFA Bourgogne (regional branch of ANELFA ), an association created in the mid-2010s to fight against hailstorms like the one that, in 2014, 2013 and 2012, had devastated the Côte de Bourgogne. Beaune remains convinced that the toll would be much higher without the network of vortex hail suppression generators. "The device was designed in 1954 by a professor from Toulouse, Mr. Dessens, at the request of Airbus, which wanted to protect its aircraft on the tarmac. Since 2017, 144 generators have been in place, Chablis south of Beaujolais "Managed by 419 volunteers who, upon receiving a hail alert, are responsible for switching on the devices at least 4 hours before the storm cells pass. The network currently protects 43,500 hectares for the modest sum of 6 euros per year per hectare, per company; it is not the only one of its kind in France, but the densest and therefore probably the most effective," explains Thiébault Huber.

Billions of particles sucked up by the storms

In the region, storms always follow the same trajectory, from southwest to northeast; the first generators are installed nearly 50 kilometers from the vineyards and the last ones in the very heart of the villages winegrowers, as in Volnay For the attached photo. Throughout their path, thunderstorms are seeded with billions of particles produced by the combustion of an acetone and silver iodide solution in generators. As the storm passes, the particles are drawn in, rising to an altitude of 10,000-12,000 meters, where they reduce the size of the icebergs, which then melt more easily as they fall, turning into water. Rainfall is increased by 10 to 15%, but you can't have everything… The generators are activated according to a precise protocol, and it is essential that all generators are switched on to avoid gaps in the system and thus achieve maximum effectiveness. "Unfortunately, the generators are not a magic bullet, but according to ARELFA, hail formation is reduced by 50%." In short, Thiébault Huber is convinced it works, and he's not alone; over a 20-year period (1990 to 2010), insurance companies observed a nearly 50% decrease in their compensation claims for crops (vineyards, fields, orchards, etc.) in areas protected by generators! The figures all point in the same direction…

Christophe TUPINIER

Publishing Director