The skies over Sioux Falls, South Dakota, turned an eerie shade of green Tuesday night as a derecho storm rolled in.
A derecho is a “widespread, long-lived wind storm associated with a band of rapidly moving showers or thunderstorms,” according to the National Oceanic and Atmospheric Administration.
The storm passed through South Dakota and other parts of the Plains on Tuesday, bringing with it powerful winds of up to 99 miles per hour in some areas.
NBC New York Meteorologist Violeta Yas explained that severe thunderstorms with a lot of water content tends to scatter blue light. When combined with red and yellow light from a sunset, "you get the green sky," Yas said.
Get Connecticut local news, weather forecasts and entertainment stories to your inbox. Sign up for NBC Connecticut newsletters.
"Keep in mind this takes a lot of water content to be able to achieve this green look. So, if you see that green sky, that could be indicative of very large hail," she added.
On social media, South Dakotans shared images of the green skies, which were also captured on the state's Department of Transportation traffic cameras.
"The green in this thing is insane! Taken in Sioux Falls South Dakota looking southwest," on person tweeted.