LOUDOUN COUNTY, Va. — “Psychedelic” – that’s how one skygazer described the colorful cloud that brightened the mid-Atlantic skies earlier this week.
According to The Washington Post, the display occurred Tuesday evening as storms moved through parts of Virginia and Maryland. Twitter users from Loudoun, Fairfax and Montgomery counties sent the newspaper photos that appeared to show a rainbow gradient in the clouds above, the Post reported.
@capitalweather @MatthewCappucci Hillsboro as the storm comes in. What is this? pic.twitter.com/a058Be5R5I
— NEsnow☮️ (@2goldens2girls) August 9, 2022
Psychedelic skies over my house in Western Loudoun! @capitalweather @dougkammerer pic.twitter.com/JYZrhPtw8f
— Travis Hare (@TheTravisHare) August 9, 2022
The phenomenon, colloquially known as “rainbow clouds,” is an example of “cloud iridescence,” according to WUSA-TV.
The National Oceanic Atmospheric Administration said the “relatively rare” sight is caused by diffraction, “when small water droplets or small ice crystals scatter the sun’s light.”
“The cloud must be thin and have lots of water droplets or ice crystals of about the same size,” the agency wrote on its SciJinks website. “When that happens, the sun’s rays encounter just a few droplets at at time. For this reason, semi-transparent clouds or clouds that are just forming are the ones most likely to have iridescence.”
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