Did you see the “rainbow clouds” on Sunday? We explain cloud iridescence

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Happy Monday and welcome to another edition of the Beyond The Forecast newsletter! We’re coming off a beautiful weekend in the Commonwealth, which included reports of an uncommon sight in Sunday’s afternoon sky.

We received numerous photos from folks in the Roanoke Valley of “rainbow clouds.” The picture at the top of this newsletter is from Kelly Camden Guill in Bonsack.

Below, you’ll see a nice photo from WSLS’s Samantha Smith at Green Goat in Roanoke.

Another WSLS employee, Rafael Ibarra, passed along this gorgeous photo of Sunday’s pretty phenomenon. But what are we seeing here?

The vibrant colors you’re seeing in these photos are caused by cloud iridescence. The sun’s rays get scattered by small ice crystals or water droplets.

The clouds must be optically thin, due to the requirement that the light only encounters one crystal or droplet. Thus, you’ll typically see the soap bubble-like colors on the edge of cirrus clouds.


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