COLUMBUS, Ohio (WCMH) — Central Ohio had a brief and unusually vivid display of cloud iridescence in the early afternoon Thursday, referred to as “rainbow clouds,” within a field of cirrus.
The colors result from diffraction, or bending, of sunlight around small ice crystals.
The distribution and uniformity of ice crystals in high, thin cirrus visible over central Ohio, perhaps coupled with strong upper-level winds that spread out or upswept the clouds, created a perfect setting for these iridescent clouds.
The effect is similar to when you see colors produced by soapy water or a film of oil. The colors represent different frequencies of light, which are reflected in a way that our eyes perceive the various colors that resemble a watercolor painting.
The physics of diffraction requires light to be bent around tiny, relatively round ice crystals, which breaks up the light into the colors of the spectrum. The higher the altitude of the clouds and proximity to the sun relative to the observer provided the best display of cloud iridescence captured by our NBC4 viewers.
Diffraction differs from refraction that produces rainbows and halos in the presence of raindrops and ice crystals, where the bending of light waves occurs passing through two different mediums.