Return of cold in France brings frost and heavy snow, vineyards at risk

A sharp drop in temperatures across much of France is leading to a return of winter weather in the Alps and the risk of “irreversible” damage to crops, including vineyards in northern and central regions.

Heavy snowfall was already underway Thursday (March 26) in Savoie and Haute-Savoie, with La Chaîne Météo (owned by Le Figaro group) reporting that “significantly colder air at altitude” is expected towards the end of the week.

Forecasters are predicting that the sudden cold snap, accompanied by polar winds, will be most severe in the Northern Alps, in particular on mountain slopes exposed to prevailing north-westerly winds. This includes the Chartreuse and Belledonne ranges, as well as the Beaufortain and the Mont Blanc massif.

Snowdrift risk for alpine roads

Meteorologists are also warning about the possibility of snowdrifts blocking alpine roads as the strong north-westerly winds blow snowfall over ridges and exposed areas. While La Chaîne Météo noted that the return of winter weather was “fairly typical” for the season, it was likely to be severe enough to affect traffic conditions at lower altitudes.

The Northern Alps region is expected to be hit with snowfall of 15 to 20cm at altitudes of 1,200m, around 30cm at 1,800m, and up to 40cm at 2,500m. Between 2 to 5cm of snow is expected to fall by Friday morning at altitudes over 600m in Savoie, 10 to 15cm at around 800m, 20cm at 1,000m, 25 to 30cm at 1,500m, and 30 to 40cm above 2,000m.

The snowfalls are forecast to be slightly less heavy towards Haute-Maurienne, with altitudes of 1,700m and above in the region expected to receive between 15 to 20cm of snow by Friday.

The snow is expected to ease on Friday, with further snowfall forecast on Saturday and again on Monday at heights of 700–800m in the region.

Burgundy vineyards fear frost effects 

At the same time, winemakers in central and northern France are bracing themselves for the impact of frost, which is forecast to hit the region later this week.

“We're holding our breath, the wind chill is forecast at 3C,” Marine Ferrand, Head of Communications for the Ferrand Estate located in Charnay-lès-Mâcon in southern Burgundy, told France3. “It absolutely mustn't drop below -1C, and we absolutely mustn't get any rain before then. If it's wet, it risks completely burning the buds.”

The recent warm weather has led to many vines budding early. In the early stage of budding (débourrement), the vine is extremely susceptible to colder temperatures, and in some cases severe frosts can wipe out a whole vineyard’s harvest overnight.

To protect their vineyards against spring frost, many French winemakers still rely on the ancient technique of using candles (bougies antigel) to warm the vines. Thousands of candles – usually metal pots filled with paraffin wax – are placed throughout the vineyard in order to raise the vines' ambient temperature. 

Fruit orchards face irreversible damage

While vines damaged by frost are capable of a second budding, the risk is much greater for fruit crops that only bud once.

“Irreversible is the word, since pear, apple, and apricot trees only flower once a year,” Serge Zaka, an agro-climatologist specialising in the effects of climate change, told FranceInfo. “We only have one flowering period per year, so if the flowering is lost, the entire harvest is lost.”

Mr Zaka said that north-east France needed to be particularly closely monitored.

"In northeastern France, from Clermont-Ferrand to Alsace, we will be monitoring the night from Thursday to Friday, then Friday to Saturday, when this cold spell will shift towards the Rhône Valley and towards the Mediterranean hinterland," he said.

Mr Zaka noted that while it was normal to experience significant day-to-day temperature variations during spring, the problem was not the sudden drop in temperature so much as the long period of warm weather that has preceded it.

“For about two months, we had temperatures above seasonal norms almost every day, even 61 consecutive days - that's the official record that was broken this year. Now, there is indeed a drop, but the problem isn't the drop itself, but the starting point.”