Video loading...
On July 5, local time, the city of Sioux Falls, South Dakota, was hit by a strong storm, causing the sky in some areas to turn green.
According to the National Weather Service, the storm that struck the city of Sioux Falls was "Dreyjo Storm," a large, long-lasting linear storm with winds of more than 58 mph (about 93 km/h).
The Bureau of Meteorology said the green color of the sky was related to the principle of optics. In the evening, as the sun approaches the horizon, the sky takes on a reddish tinge. Water or ice particles in thunderstorms mainly scatter blue light. When the scattered reddish light in the atmosphere illuminates the water or ice particles in the cloud, a green light is produced. The Bureau of Meteorology also added that a lot of water is needed in thunderstorms to produce this green color, which often indicates that the storm will bring hail.
The National Weather Service reported hail in some areas with winds as high as 90 mph (about 145 km/h). In addition to South Dakota, the strong storm affected parts of Nebraska and Iowa.
(Editor: Liu Qingyang)