In Sioux Falls, a town in the US state of South Dakota in the north of the country, residents were able to observe a strange weather phenomenon on Tuesday evening local time. The sky turned bright green, as various pictures on social media show. The effect is most likely caused by upcoming storms – scientists are still divided on exactly how this happens.
The most common theory is that sunlight is refracted by water particles in the air. The normally red light appears green following splitting, like «watson» reports, and makes the high cloud mountains look even more threatening.