Yellow sky and sand dust, what is this phenomenon that crosses part of France?

This Tuesday, the phenomenon is visible from the Pyrenees to the Pays-de-la-Loire, via Bordeaux, Angouleme, and even as far as Auvergne-Rhône-Alpes. On Tuesday, residents of southwestern France woke up to an episode of Saharan sand dust in the air, turning the sky a yellow hue and covering vehicles with a substantial layer of sand.

According to Météo-France, these concentrations of sand dust, a phenomenon called “dust”, are indeed intense on Tuesday morning, and should continue throughout the day, before heading north on Wednesday. The phenomenon had passed through Spain on Monday.

Risk of increased particulate matter levels

Atmo Nouvelle-Aquitaine (the organization that measures air quality) specifies that “the south-easterly wind” that has been blowing especially in the Nouvelle-Aquitaine region since Monday evening “returns desert dust from the Sahara. » « Today this dust is visible in the air (orange color) and on the ground (sand washed away by rain and/or humidity). †

“This type of desert dust rising episode is quite common during these periods, but it seems especially striking in terms of its geographic scope and duration, as it will last until Thursday night,” explains. 20 minutes Gaëlle Collin, head of the Environment, Atmosphere and Health team at Météo-France. But to really qualify it will be necessary to see what was there in terms of desert dust concentration, which will be the responsibility of air quality monitoring associations. †

This situation should cause PM10 particulate contamination. Atmo Occitanie therefore predicts an exceedance of particulate matter in the Hautes Pyrénées department for this Tuesday, an episode that should continue on Wednesday. In New Aquitaine “levels of PM10 particulate matter will increase during the day and Wednesday, which could worsen Atmo’s air quality indices in certain departments, particularly in the Pyrénées-Atlantiques, where indices are expected to be bad today. and tomorrow. “

A phenomenon expected until Thursday

“There is a depression in Morocco that creates a current from the south that brings sand from the Sahara, through rifts, through Spain, and the phenomenon persists in time due to an anticyclone at the level of the Greece that the evolution of this flow, which means that the event will last” specifies Marine Jeoffrillon, from Météo-France

The phenomenon should last until Thursday evening.