What is blood rain and when is it coming to the UK?
IN historic times it was believed that blood fell from the skies and although science has explained this away, it is still a sight to behold.
Cases of blood rain date back to Homer's Iliad, although it is a rare occurrence in the UK.
What is blood rain?
Blood rain is a weather phenomenon where it looks as if blood falls as rain from the sky.
Before the 17th century it was thought this strange weather was caused by actual blood and considered a bad omen.
Any supernatural origin for the showers has since been totally debunked by modern science.
Kirsty McCabe, editor of MetMatters (the Royal Meteorological Society magazine), told The Sun: "The rain looks red as it falls, and it leaves behind a thin layer of red dust on surfaces."
"When these fall as rain – the red colour gives rise to the name blood rain," she added.
Greek epic Homer’s Iliad is the first literary reference to it when, according to the classic, Zeus causes a rain of blood.
Zeus, king of all gods, brings the rain to express grief at the death of his son Sarpedon during the Trojan War.
It is understandable the supernatural assumptions as blood rain can look ominous as the red droplets fall.
When is it coming to the UK?
The weather forecast is very turbulent in the UK this week (May 16-23, 2022), with rain, thunderstorms, and soaring temperatures across the country.
This also comes with the possibility of blood rain coming to the South East.
Blood rain is not common in the UK, as Kirsty explained: "Proper blood rain, where the rain looks red as it falls is rare in the UK as you need high concentrations of red dust particles.
"But we do have several occasions each year where the rain falling has dust mixed in with it, usually from the Sahara.
";The dust is usually yellow or brown and in fairly low concentrations.
"So the rain itself won’t look any different as it falls, but you might find it leaves behind a thin film of dust."
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Dust has blown 2,500 miles from Africa across the Sahara Desert and is now expected to fall over the UK.
After the hottest day of the year (Tuesday, May 17, 2022), thunderstorms battered much of the country on Wednesday, May 18.
This eased overnight but blood rain is yet to fall, although orange clouds could still be seen thanks to the dust in the air.
This happened in March 2022, where many cars and windows ended up covered in fine red dust.
What can cause blood rain?
A study in 2015 established that a blood rain in Kerala, India, had been caused by the aerial spores of green microalgae.
Kirsty said: "It all begins when strong winds whip up dust and sand over deserts that become airborne and can get carried for thousands of miles high in the atmosphere.
"Eventually the dust falls out of the sky due to gravity or gets caught up in rain clouds and mixes with the water droplets.";
The phenomenon is also thought to be caused by red dust or sand mixes with the precipitation.
Dust from the Sahara Desert are swept up into the atmosphere.
This collects in the rain and the clouds, resulting in the orange skies and mythic blood rain.
Despite the ominous name, the rain is mostly harmless, Kirsty said: "For most people it’s just annoying to find a layer of dust on your car or windows.
"But the additional dust in the air can affect air quality and raise levels of air pollution, which could be an issue to those with existing health conditions."
So, even though it is not as terrifying as historically believed, it can still be a nuisance leaving behind the layer of dust.