In the media, it’s gained a dramatic name, “blood rain,” but it’s actually a phenomenon that’s becoming more common in southern Europe and has a fairly down-to-earth explanation. You’ve probably seen streets and cars covered in a fine layer of mud or cities blanketed with orange dust at some point; there’s an explanation for this, and it’s the southern winds carrying dust particles from the Sahara.
Throughout the year, Sahara dust makes its way into the North Atlantic, but it’s from late spring that it starts to become more noticeable, especially in the Caribbean Sea and northern South America. This makes sunrises and sunsets appear more vibrant, and with it comes a phenomenon known as blood rain.
Blood Rain in Greece: The Explanation Behind This Phenomenon
The city of Athens and other regions in southern Greece have been hit by a large plume of Sahara dust that has turned several areas a shade of orange. This is airborne dust that arrived from Africa this Tuesday, creating some surprising visuals. Some people even joked that it “looks like Mars.” However, the mass of air carrying the Sahara dust, which is between three and four kilometers thick and about 1.5 km high, is warm and dry, and given the precipitation and winds, the particles travel far enough to cover houses, cars, and terraces with red dust.
“Blood rain,” as this phenomenon is known, doesn’t mean blood drops falling from the sky, but the Sahara sand gives it a reddish hue that can remind you of blood, and its intensity depends on how much dust has condensed in the air. Usually, we see a blue sky because, of all the colors, this is the one most scattered by our atmosphere’s molecules, except at sunrise and sunset, where reddish and orange tones dominate because the sun’s rays pass through a larger volume of the atmosphere.
So, when there’s a high concentration of dust, the sun’s rays interact with these particles to create a filter that intensifies the warm tones in the sky, which is why we can see fiery shades.
Is Blood Rain Caused by Warm Air and Dust Particles?
The water droplets in our atmosphere are not just made of water; they need a “condensation nucleus” to gain enough size to fall due to their weight. These nuclei can be mineral salts, organic matter, bacteria, or dust in suspension. The ground heats up, and particles are lifted and carried over long distances by the wind. Once these particles are in suspension, they attach to evaporated water droplets and end up falling as mud, while the dust changes the color of the air.
Although it can feel like you’re in a science fiction movie when this phenomenon occurs, the truth is that this type of rain is quite beneficial for farmlands and plants in general. Desert sand brings numerous nutrients to vegetation.
This story was written in Spanish by Perla Vallejo in Ecoosfera.
