South Dakota’s most populous city experienced its own version of Orange Sky Day this week after South Dakotans woke up on the morning of July 5 to find their skies green.
The meteorological phenomenon is attributed to a powerful storm called a derecho. According to the National Weather Service, a derecho is a widespread (extending more than 240 miles) and long-lasting wind storm with fast-moving rain or thunderstorms.
The wind storm swept across South Dakota and the surrounding Great Plains on Tuesday, where gusts were reported to reach 99 mph in some regions.
The skyline of Sioux Falls, South Dakota on Tuesday, July 5.
Courtesy of Jaden (@jkarmill)
Although it appears that derecho is the cause of the green sky, the science explaining the unique coloring is debated among meteorologists.
In 1993, a study from Penn State University investigated whether hail was the cause of the green color, but concluded that its effect was weak. Instead, the study’s co-authors proposed two plausible theories, and they differ in the sun’s position. Craig Boren theorizes that the green is caused by the setting or rising sun (providing the yellowish color) shining behind a thunderstorm with rain or hail that has a bluish tint. Alistair Fraser claims this is due to the sunlight before the thunderstorm. Both researchers agree that for a green sky to appear, there must be a powerful thunderstorm carrying a large amount of precipitation precisely aligned with the sun.
During this week’s storm, South Dakotans shared their reactions to the green skies on social media:
Oh my gosh! See how green the sky is before severe storms near Sioux Falls, SD! #sdwx pic.twitter.com/fc7fpN6loL
— Chris Michaels (@WSLS_Michaels) July 5, 2022
The green sky photos from my family in Sioux Falls were amazing! I had to dig up this fun green cloud infographic I made back in the day. Hail is reported not to be very large right now, but the storms are very wet in this warm, tropical environment. #SDwx #IAwx pic.twitter.com/S39JLSRfEu
— Cory Martin (@cory_martin) July 5, 2022
The green in this thing is insane! Taken in Sioux Falls, South Dakota, looking southwest. #sdwx pic.twitter.com/x7Yx6UE2wF
— Tanner Charles 🌪 (@TannerCharlesMN) July 5, 2022
For local weather news, visit the SFGATE Weather page.
Add Comment