Eerie Pink Sky Appears Above Dallas

The Dallas sky was glowing a strange pink-purple color on Tuesday morning and it seemed to unnerve at least one Reddit user.

The Reddit post sharing the picture, posted by user u/s0c-Magget, has gone viral, garnering over 12,000 upvotes.

"Not a filter, Dallas[-Fort Worth] has a pink sky today???? I haven't even lived here for a year what does this mean??" wrote u/s0c-Magget in the caption of the picture posted on Tuesday.

While clouds usually appear white because they scatter all light wavelengths, the atmosphere itself is better at scattering short wavelengths of visible light such as blue than long wavelengths of visible light such as red/pink. This is why the sky appears blue during a clear day: the blue wavelengths of sunlight are scattered across the sky.

However, if a storm happens near sunrise or sunset, then the clouds may appear pink or orange.

"[This is] because the sunlight is coming at you, the observer, at a very low angle in the sky, and has to pass through more of the denser part of the atmosphere than during mid-day," William Gallus, a professor of meteorology at Iowa State University, told Newsweek.

"This means even more blue light is scattered away than normal. With all the blue (short wavelength light) scattered away, the sun acts kind of like a red or orange flashlight shining on the clouds, making them look orange or red or pink."

The idea that a red sky forewarns of an oncoming storm dates back hundreds of years, even being mentioned in the Bible, in Matthew 16:2-3: "When it is evening, you say, 'It will be fair weather; for the sky is red.' And in the morning, 'It will be stormy today, for the sky is red and threatening.'"

A folk saying "red sky in the morning, sailor's warning, red sky at night, sailor's delight" claims that a dawn red sky means a storm will occur during the day.

This is also due to the scattering of light, but it also has to do with the direction of the sun's movement across the sky, and the direction that storm cells tend to travel.

"The other part of that story is that storms tend to travel west to east (at least in mid-latitudes, outside of the tropics)," Jeffrey R. French, an assistant professor of atmospheric science at the University of Wyoming, told Newsweek. "In the morning, the sun is in the east and reddish-illuminated clouds will be in the west. With clouds moving west to east, they would move towards the observer (i.e. take warning....clouds moving our way). In the evening, the sun is in the west and reddish-illuminated clouds will be in the east, moving away from the observer (i.e. sailors delight....clouds moving away from us)."

In the comments of the viral Reddit post, users also remarked that a green sky was an omen of a tornado coming soon.

"I remember living in Oklahoma for a year right around when that really bad tornado destroyed a town in 2013, the clouds were this very erie green," wrote u/ElFuegoFlavorTown in a comment.

"If it turns green.... Shelter. Immediately," wrote another user, u/DeviantInDisguise.

This phenomenon is due to the clouds containing a high amount of water, therefore only allowing the blue-green wavelengths of light to pass through.

"Green clouds are rare and tend to be associated with very high water or ice content in a cloud, since liquid and frozen water absorb red light, plus they need the sun to be at the right angle and not obscured by other clouds," Steven Sherwood, a professor of atmospheric sciences at UNSW Sydney in Australia, told Newsweek.

"These clouds are often associated with severe thunderstorms."

Newsweek could not verify the authenticity of the picture.

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about ? Let us know via science@newsweek.com.