We all know to avoid yellow snow. But locals and holiday-makers in Eastern Europe have been baffled by a phenomenon that appears to be turning snow orange.
People have taken to social media to post photos of the spooky orange snow that has blanketed countries such as Russia, Bulgaria, Ukraine, Romania and Moldova.
The snow has also fallen on the slopes at Russia’s Sochi ski resort — the venue of the 2014 Winter Olympics — which now resembles a “Martian landscape” and has drawn references to the apocalypse, Russia’s television network RT reported.
So what on Earth is going on?
The orange snow is a phenomenon that happens once every five years or so, experts say.
Steven Keates, a meteorologist from the UK national weather service, said it was caused by desert sand drifting in from Africa.
“There has been a lot of lifted sand or dust originating from North Africa and the Sahara, from sandstorms which have formed in the desert,” Keates told The Independent.
“As the sand gets lifted to the upper levels of the atmosphere, it gets distributed elsewhere.”
“Looking at satellite imagery from NASA, it shows a lot of sand and dust in the atmosphere drifting across the Mediterranean. When it rains or snows, it drags down whatever is up there, if there is sand in the atmosphere.”
The phenomenon has happened in other parts of the world as well, Keates said.
In January, residents of a town in central Kazakhstan said air pollution from the local iron and steel industry had left it covered in black snow.
And Sydney residents will remember the dust storm that covered the whole city with a bright red haze for one day in 2009.
The rare event was the result of the sun hitting a blanket of dust that had been brought in by strong winds from drought-affected parts of inland New South Wales and South Australia.