What is blood rain and will it hit parts of the UK this week?

There could be blood rain in the UK this week as severe thunderstorms mix with a cloud of dust, forecasters say.

Red or orange rain could fall in some parts of the country as downpours, lightning, high winds and hail hit.

But what is blood rain, where does it occur, how often does it fall and is it actually red? Here’s what you need to know.

According to the Met Office, the phenomenon known as blood rain occurs when relatively high concentrations of red-colored dust or particles mix with rain, giving it a red appearance as it falls.

Strong winds or storms can kick up dust and sand, and when it gets airborne, it circulates and can be carried thousands of miles.

The dust can also cause vivid sunsets.

The Met Office website states: “Eventually the dust will either fall from the sky due to gravity or be caught by rain clouds where it will mix with the water droplets. If these fall as rain, the raindrops could appear red.”

The Met Office says it’s actually not that common to get actual blood rain where it would appear red. This is because there would have to be fairly high concentrations of red dust in the rain for it to occur.

There are few documented cases, including one in 2001 in the southern Indian state of Kerala. It saw regular monsoon rains fall with a red color dark enough to stain clothing.

While the term blood rain is used in the UK, the dust is more likely to be yellow or brown.

The Met Office website states: “Several times each year there will be rain mixed with a certain amount of dust in the UK. This usually comes out of the Sahara before mixing with clouds and falling out.

“However, the dust we see is usually yellow or brown and mixed in very low concentrations – so the rain would look the same as usual. The only difference would be that after the water has evaporated, you might find a thin film of dust on your car or windows.”

A cloud of Saharan dust is making its way across the Atlantic and is expected to reach western Europe and then south-east England on Friday.

Richard Miles of the Met Office told the PA news agency: “There are currently some levels of dust in the atmosphere over the UK that could be washed out by the rain tonight, but overall the levels are likely to be relatively small.”

It comes as a yellow thunderstorm weather warning was also issued in the south east, including London, from Wednesday evening into the early hours of Thursday, saying people should expect travel disruptions.

Heavy rain is expected in parts of Scotland and Northern Ireland on Wednesday and Thursday, while showers will also hit areas in Wales and central and south-west England.