Weather adages abound. We’ve all heard a version of “red sky at night, sailors’ delight; red sky at morning, sailors take warning.”
But the sky pulled a new one on the Great Plains on Tuesday, turning green as a powerful windstorm swept through South Dakota and other states.
“I think it caught a lot of people’s attention because the sky did have that very unique green color to it,” Peter Rogers, a National Weather Service meteorologist in Sioux Falls, told The New York Times.
“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,” he said.
Twitter was awash with images from the event.
GOODNESS GREEN. This is a look at the sky in Sioux Falls right now as severe storms push through from one of the DOT cams. #SDwx @foxweather pic.twitter.com/VhSEvxpE1D
— Heather Brinkmann (@WeatherHx) July 5, 2022
Green Sky’s all of the sudden in South Dakota USA … pic.twitter.com/BxMIolG6mZ
— ⚡️hamaryah Ban Yahawadah ????? (@eddiedevonne) July 5, 2022
Sioux Falls, SD #sdwx pic.twitter.com/uH8hRKbA4G
— Nathen Erickson (@TwstdSkyStudios) July 6, 2022
West of Beaver Creek, MN a few moments ago. Amazing green hue as the storm approaches. Staying ahead for now. #mnwx #sdwx @NWSSiouxFalls pic.twitter.com/RigteC5Ccn
— John Homenuk (@jhomenuk) July 5, 2022
Video of the green sky behind the wall cloud as it passes Sioux Falls, SD
? SoDakZak on Reddit pic.twitter.com/RzsnKwX19R
— Discover Earth ?? (@discoverearthhq) July 6, 2022
The green sky was associated with a powerful wind storm known in weatherspeak as a derecho. The storm spanned about 240 miles of South Dakota and the adjoining plains and had winds of up to 99 mph.
It also packed a lot of moisture, according to Fox Weather, which meant the light refracted off it in a very unusual way.
Green skies can be an indicator of a major hail storm, the National Weather Service said.
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“Water/ice particles in storm clouds with substantial depth and water content will primarily scatter blue light. When the reddish light scattered by the atmosphere illuminates the blue water/ice droplets in the cloud, they will appear to glow green,” the service explained, according to PBS.
A one-inch hailstone was reported in Sioux Falls, and a 2.75-inch hailstone was reported in Lake Wilson, Minnesota.
Penn State professor Craig Bohren said a late-day storm can trigger the effect of a green sky, according to AccuWeather.
As the sun sinks, he said, its light shifts along the spectrum.
“When this setting light is transmitted by a massively thick cloud composed of water droplets and ice particles, the results are a green sky,” Bohren said.
The storm Tuesday produced high winds across the region. At the Sioux Falls Regional Airport, winds peaked at 80 mph and were above 58 mph for about 45 minutes, according to the National Weather Service.
How long did the severe level winds last at the Sioux Falls airport?
Observations show that the airport reported nearly 45 minutes of winds at or above the severe thunderstorm criteria (58 mph), with a peak of 80 mph. pic.twitter.com/ZlcK1wGNvj
— NWS Sioux Falls (@NWSSiouxFalls) July 6, 2022
“When you’re talking wind speeds of that magnitude, it’s synonymous with a weaker tornado or a low-end tornado,” Rogers said. “They’re tornado-like wind speeds.”
This article appeared originally on The Western Journal.
