The arrival of spring also punctuates with the return of the risk of spring frost on French territory.
After a winter which was abnormally mild (+2°C), particularly at the end of January-beginning of February in the South, the arrival of the spring frost poses very significant risks for farmers, particularly in the vines where the fight Against this meteorological phenomenon is an annual battle.
White frosts, located on the ground with temperatures often between 1 and 2°C in the plains, are making their first appearances later than expected this year due to the heat of winter.
What is spring frost?
As its name suggests, spring frost generally begins in March or April.
Concretely, hoar frosts often occur with
“a clear sky at night and in weak winds”
, according to
La Chaîne Météo
*, which allows
“significant radiation”
which cools the ground and the layer of air above it.
In the event of negative temperatures, the water vapor present in the air changes to a solid state.
“The ice crystals formed are deposited on the ground, cars and vegetation: the famous frosts which whiten the landscapes in the morning
,” concludes the weather channel.
On the other hand, be careful not to confuse white frosts with frost and black ice, which are both in a state of supercooling.
The different types of possible jellies.
The Weather Channel
Who is particularly affected by this phenomenon?
Crops will be the first to face this common phenomenon, particularly vineyards and fruit trees.
Episodes of black frost, such as in 1991, have had their mark on agricultural professions, but it is global warming that would in fact be responsible for disruption.
With a shorter and less cold winter,
“the risks of damage linked to frost increase significantly due to the advance of vegetation caused by these increasingly mild conditions”
, continues Cyril Wuest, meteorologist from
La Chaîne Météo
.
As a result, the vegetation is very early this year.
“With the precocity of flowering and budburst, the period of conjunction between the risk of frost and flowering creates a longer period of vulnerability than in a normal year where flowering begins later
,” says Cyril Wuest.
Where an apple tree resists low temperatures (-7°C) at the start of bud swelling, the situation is completely different during flowering: it will not be able to withstand only -2°C.
The same goes for young leaves.
The later a spring frost period arrives, the more devastating it can be.
The usual period which ran until May now ends at the end of April.
Obviously, the losses are colossal: La Chaîne Météo* estimates the losses following the late frosts of April 2021 and 2022 at two billion euros.
*The Weather Channel is a property of the Figaro group.