The skies over parts of Britain took on a soft pink hue on Wednesday morning as the low sun shone through layers of thick fog, creating a rare atmospheric treat.
Met Office meteorologists said the fog formed as temperatures dropped overnight. They issued a yellow warning for a large area of the central and northern part of the country. England where the fog cleared slowly and remained in force until 10am.
Areas of particularly dense fog developed in the East Midlands and Cambridgeshire, where poor visibility was expected to lead to difficult travel conditions.
Like clouds, fog is created by tiny droplets of water suspended in the air. It may appear pink because water droplets scatter the short wavelengths of sunlight—blue and green—more than the longer red waves, allowing the red color to dominate.
Pink color is usually visible at the beginning and end of the day when the sun is low on the horizon and sunlight passes through more of the atmosphere than when it is higher in the sky.
A Met Office spokesman said: “Fog is essentially a cloud at ground level made up of tiny droplets of water. When the sun is low on the horizon, its light passes through most of the atmosphere. The shorter wavelengths are scattered, leaving the longer red wavelengths to dominate. When this filtered light shines through the fog, it gives the fog a rosy or rosy hue.”
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Cobwebs covered with dew drops, pink mist envelops the countryside at dawn, Dunsden, Oxfordshire.
Despite the surreal appearance, it is nothing more than the physics of light playing at sunrise and sunset.
“It’s important to note that pink mist is a purely optical effect,” the spokesperson said. “This does not indicate any unusual weather hazards beyond the normal risks of fog, such as reduced visibility.”
This phenomenon has already been noticed in the UK. In 2019, early morning skies turned pink as fog formed over parts of south-west England.
But Dr Claire Ryder, associate professor at the University of Reading, said the effect was rare because there had to be several ideal conditions for the pink color to occur.
“This effect is caused by the reddish sunrise being 'filtered' by the fog. The sunrise creates red light, removing the bluer colors, and then small droplets of fog scatter the light further, darkening the effect, giving it a muted pink glow,” she said.
“It's quite an interesting and rare phenomenon: to get the right effect, you need the fog to occur at the exact time of sunrise or sunset, and the fog to have the ideal thickness or droplet concentration and size. Too thick a fog will block all the light, and too thin a fog won't dull the colors of the sunrise much.”
