Residents in Sioux Falls, South Dakota, witnessed a bizarre phenomenon in the skies earlier this week.
On Tuesday (July 5), locals in the city were amazed as the sky above them resembled a scene you'd expect to find in a sci-fi movie.
Speaking to the Daily Mail about the incredible sight, AccuWeather meteorologist Isaac Longley said: "While it is relatively common to see these green skies, especially in the Plains, the skies associated with the severe storms that pushed through Sioux Falls during the afternoon of July 5th appeared even greener than normal.
"This, of course, caught the attention of many who had never seen skies so green."
Explaining how the fascinating green hue occurs, Longley explained: "Thunderstorms tend to occur later in the day due to the sun's energy during the day helping to fuel them.
"As many of us know, the sun appears redder later in the day as it approaches the horizon. However, light underneath a tall thundercloud appears blue due to the scattering by water droplets.
"When the blue light is illuminated by the red light from the setting sun, it appears green, which is why some thunderstorms have that greenish hue to it."
Longley added that the green skies were visible for around 10-20 minutes.
Taking to social media to share their thoughts and images on the green skies, one resident tweeted: "The Green Monster over Sioux Falls yesterday. The most eerie storm I’ve ever witnessed."
A second added: "Oh my gosh! Look at how green the sky is ahead of severe storms near Sioux Falls, SD!"
"The green in this thing is insane! Taken in Sioux Falls South Dakota looking south west," a third wrote.
"Have never seen something like that," another resident added. "Green sky with combination of blue in Sioux falls SD".
And the amazing pics and videos kept coming:
A further notice from NWS Sioux Falls shared to Twitter added: "After discussing with SPC, today's still ongoing thunderstorm complex will be considered a derecho.
"The peak winds so far have been 96 mph in Huron, SD and 99 mph near Howard, SD but there have been many high wind reports."
