Skies bizarrely turn green in South Dakota before derecho storm

The skies above South Dakota turned a peculiar shade of green on Tuesday (5 July) as a derecho storm rolled in.

According to National Weather Service Sioux Falls, the storm brought winds close to 100 mph in some areas, meaning the “thunderstorm complex will be considered a derecho”.

A derecho storm is defined as a “widespread, long-lived wind storm associated with a band of rapidly moving showers or thunderstorms” by the National Oceanic and Atmospheric Administration.

The National Weather Service also says a derecho classification applies “if the wind damage swath extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length”.

In South Dakota, residents there have grown used to derechos having recently experienced two such storms. However, the green sky was a highly unusual sight and drew far more people’s attention, with some posting images online.

One person posted: “Green Sky’s all of the sudden in South Dakota USA …”

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A meteorologist wrote: “Oh my gosh! Look at how green the sky is ahead of severe storms near Sioux Falls, SD!”

One photographer posted an image and explained: "No filter. I have never seen the sky that color of green before, it was almost eerie."

Meteorologist Peter Rogers told NY Times: “I think it caught a lot of people’s attention because the sky did have that very unique green color to it.

“Because of the unique color that it did exhibit, I’m guessing that it will probably be a topic of discussion for quite a long time.”

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