Scientists in France are calling on the public to help them analyse grains of Sahara sand embedded in snow, to test its chemical properties and help inform future weather models.
Researchers in Toulouse and Grenoble have asked members of the public to gather and send samples of this “orange snow” - snow with grains of sand embedded within it - to help with their analysis.
The study is being conducted by snow study centre le Centre d’études de la neige in Toulouse, and geosciences institute l’Institut des Géosciences de l’environnement in Grenoble.
It comes after France saw “dramatic orange skies” over Toulouse, Lyon and Grenoble earlier this month, caused by Sahara sand. The phenomenon this year coincided with heavy snowfall in much of the country, hence the mix.
#tempête de #sable au nord-est du Maroc, avec des vents soufflant à plus de 100 km/h en altitude, et des températures localement proches de 27°C. Ce sable remonte déjà vers la France. Nabil Kaichouh pic.twitter.com/TcEg1dXAUZ— La Chaîne Météo (@lachainemeteo) February 5, 2021
Phénomène naturel garanti sans filtre.— Préfet de région Auvergne-Rhône-Alpes et du Rhône (@prefetrhone) February 6, 2021
Un puissant flux de sud transporte le sable du #sahara ce qui rend la couleur du #ciel particulière aujourd’hui à #Lyon et dans le reste du département. pic.twitter.com/g44FDzAeQd
Dr Marie Dumont, director of snow studies at a Météo France research unit based at Grenoble University, told news source Le Dauphiné: “Deposits of Saharan sand do happen, but usually later in the year.
“The intensity varies a lot too, but this episode was intense and spectacular for many people. And this has an impact on the accelerated melting of the snow, which can last from 5-6 days…[and even] up to 40 days at high altitude.”
Samples of the sand-flecked snow have been sent in from across the country, Dr Dumont said.
The scientists filter, dry then weigh the particles; and some of the samples are kept frozen to allow researchers to study the average size of the particles.
Dr Dumont said: “As a researcher it is great to see this cooperation between us and the public.”