Between excessive use of vigilance and more moderate reality: weather under pressure

Intense cold affects France in mid-January and several departments are placed on alert. Certainly, the temperatures observed are negative but far removed from those known in the past. Meteorologists criticize excessive vigilance, often alarmist, which generates unrealistic expectations among the public. An overestimation of weather phenomena linked to excessive consumption of forecasts does not always reflect reality.

Winter 1956. France and the Grand Est are hit by a cold wave, “devastating, brutal and lasting”, according to Météo France. For three weeks, between 1^is January and 1^is February, temperatures drop ever lower, from -18 to -20°C.

Haute-Marne, for example, and Langres, are often considered to be areas where the cold reigns. You only need to analyze a weather map of France to realize that the city with its ramparts is often in the blue.

In 1956, Langres experienced two records, on February 2, the mercury showed -20.8°C, eight days later, on February 10, it was -20.8. A few kilometers away, in Chaumont, Saturday February 18, 1956 was freezing: -20.6°C.

As we used to say in the cottages: a “beggar’s cold”. An expression whose comparison is sufficient in itself; the “beggars”, having no home and too poor to be dressed warmly enough, often suffered from the cold.

And for this Tuesday, January 14, 2025? What about it? All the media use vocabulary in their headlines, sometimes alarmist.

Thus, readers and Internet users can read: “Update on the freezing temperatures in France this Tuesday?”, or “34 departments on yellow alert, widespread negative temperatures”, or even “how long will this period of great cold in France?

In Haute-Marne, on average, temperatures did not fall below… -10°C. Only at night. The mercury quickly rose to become positive by mid-morning.

“There is sometimes imprecise terminology in the media, particularly when it comes to weather forecasting. These terms are not always used wisely”points out Alexandre Berger, president of the Haute-Marne climatology association. “A “cold wave” is a very precise term, which requires certain criteria to be respected.”

“I blame all these sites which go beyond what the weather can do. We see forecasts for 10 or even 15 days. It's not possible. Beyond six days, we don't know.”

Louis Bodin, meteorologist

Indeed, for a meteorological event to be qualified as a “cold wave”, the criteria are draconian: temperatures must be recorded over a large spatial extent, the average temperature over the day must be at least 0.9 °C over three days, and finally, out of these three days, have at least one where the national average falls below the bar
– 2°C. The mercury is far from that, this Monday January 13, the average was 1.1°C.

“Once we analyze this, we realize that we are far from the cold snap. It’s just a cold snap, and certainly not an exceptional situation”procrastinates Alexandre Berger, while recalling that the harshest winter periods were those of February 1956, January 1985 and December 2009.

Summer and winter, whether it's raining, windy, stormy or snowing, vigilance is now very much – too much? – numerous, whether transmitted by media or telephone, a tool by which insurance companies warn customers. Louis Bodin, meteorologist on TF1 and RTL, is worried about this.

While he agrees that weather alerts and warnings are also there to protect citizens, he also thinks “that we are going a little far. And, indeed, by crying wolf, we can now ask ourselves the question of the importance of vigilance. And therefore we can create this doubt, which unfortunately is against -productive in relation to what we look for in the weather forecast”.

25 years ago, the meteorologist considers that he would not have paid attention to last week's windy episode. Winds of 100 km/h in winter are, according to him, a usual and typical occurrence of the period.

“Our weather forecasts take into account societal developments over the last 30 years. Today, like many other things, we consume these weather alerts, we become very dependent on them, when very often, they are just the right thing to do. sense”underlines the meteorologist. “We have lost a little sense of observation and adaptation. We have to re-educate ourselves in this, because that is also weather forecasting.”

Meteorology is a complex science. Forecasts are even more so, because they are limited to three axes of analysis: the randomness of meteorological events, the data recorded and the time necessary to analyze them.

For Alexandre Berger: “It is better to be vigilant and overestimate a weather phenomenon than to relive storm 99, which was clearly too underestimated”. Louis Bodin remembers: “This storm was and still is a great trauma for the profession. Moreover, there was a before and an after and vigilance was regularized. Likewise, progress, often technological, was made”.

The number of computers in stations has increased significantly, satellite programs have developed. Modeling software has been created to improve precision. “But this is still a forecast. Over the next 24 hours, we can be 95% sure. But there remains this unknown part of 5%, which is difficult to anticipate.” It’s up to Alexandre Berger to conclude: “We are still moving towards better things. Especially since artificial intelligence should be revolutionary in the context of meteorology.”

Finally, the two meteorologists also agree on another point which would explain this overdose and overestimation of vigilance. Since these bulletins are “consumed”, the “consumers” are more and more demanding. “And I blame all these sites that go beyond what the weather can do,” underlines Louis Bodin. “We see forecasts for 10 or even 15 days. This is not possible. Beyond six days, we don’t know.”

For Alexandre Berger, “we also want to know what the weather is going to be like, to the nearest hour, to the nearest kilometer. We ask the weather to have an increasingly fine spatio-temporal scale, which is very difficult to envisage with regard to this science.”