A hard rain is going to fall. Dust plumes, whipped up by winds over the Sahara Desert, are moving over western Europe. This annual phenomenon—known in Spanish as “La Calima,” which literally translates to “the haze”—means a plume of dust and sand is threatening an area covering Spain, Portugal and France.
“Blood rain”—essentially falling red mud created by the sand and precipitation mixing together—is expected, as are hazardous air conditions and, of course, a red haze. The conditions could last days, according to some forecasts. The rain, despite its name, is not harmful in itself. But public health authorities are urging older people, children and people with respiratory issues to limit their time outdoors so as not to inhale the dust.
Dust from the Sahara covers a car in Madrid in 2022.
Marcos del Mazo/LightRocket via Getty Images
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Every year tens of millions of tons of particulate matter from the Sahara is swept up into the air and dispersed across the globe, with some dust even reaching the Americas.
This plume appears to be driven by a local weather phenomenon known as DANA (an acronym for “isolated depression at high levels” in Spanish), which is an isolated high-altitude depression that forms when cold air meets warm air above the Mediterranean Sea, causing hotter air to rapidly rise and form dense clouds. When a DANA and La Calima combine, they can create severe and even dangerous weather conditions over the region.