Clouds of dust have engulfed Athens and other Greek cities, turning the sky an apocalyptic orange.

The dust originated from the Sahara desert and blew across the Mediterranean Sea on strong northwesterly winds, reaching Greece Tuesday (April 23). Skies over the Acropolis and other Greek landmarks turned a dramatic, fiery hue, prompting Greek authorities to issue a health warning over fine dust particles in the air.

The event is predicted to clear from Wednesday onward as winds start blowing eastward.

"The strong Saharan dust transfer event called Minerva Red that is occurring in our country is expected to recede," Lagouvardos Kostas, a meteorologist and research director at the National Observatory of Athens, wrote in a Facebook post. "The dominance of west-northwest winds will result in the progressive transfer of high dust concentrations to the Aegean, while on Thursday [April 25] the high concentrations of dust will be detected in the Dodecanese," Greek islands in the southeastern Aegean Sea.

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In an April 23 Facebook post, Kostas compared Athens smothered by the orange haze to a "colony on Mars."

The weather event is "one of the most serious episodes of dust and sand concentrations from the Sahara since March 21-22, 2018, when the clouds invaded the island of Crete in particular," Kostas told the France Media Agency (AFP) and Associated Press (AP).

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But Saharan dust storms are relatively common, with clouds previously riding northerly winds to Greece in late March and early April. Dust storms earlier this month also carried fine particles to Switzerland and southern France, the AFP and AP reported.

Between 66 million and 220 million tons (60 million to 200 million metric tons) of mineral dust are whipped up from the Sahara every year, according to the AP. The largest particles quickly fall back down, but the smallest specks can travel thousands of miles across Europe. Saharan dust clouds can also cross the Atlantic Ocean, sometimes reaching and providing fertilizer for the Amazon.