The sky in the US state of South Dakota turned an eerie shade of green in early July before severe weather swept through the area.
While the considerable rain, hail and wind that hit the state was nothing new to residents, the colour of the sky was something straight out of a sci-fi movie.
Why was the sky green in South Dakota?
Residents of Sioux Falls, South Dakota took to Twitter to share photos of the eerie phenomenon, which was caused by a derecho.
The unusual colours before or during a storm can sometimes occur depending on how sunlight interacts and scatters amount different particles in the atmosphere. Green skies before or during a thunderstorm can be an indicator of strong hail.
The orange sky in Spain
This phenomenon isn’t exclusive to the United States. The sky changed colour in Spain in March, when dust and sand from the Sahara desert covered the skies and turned them orange.
The Climatology Laboratory of the University of Alicante warned citizens not to stay outdoors for long periods of time due to the poor air quality caused by the weather phenomenon.
