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Published on: 6/4/2009
Last Visited: 6/4/2009
News 8 meteorologist Matt Zidle said what is often referred to as a "rainbow cloud" is actually a tangent or circum-horizontal arc.
He said the phenomenon is not seen very often and usually appears as a brighter-colored spot on a halo.
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Witnesses said there was no halo visible in the arc on Monday, but Zidle said at this time of year, when the solar angle is greatest, is when these occur.
He said the sun's rays hit the ice crystals in a cirrus or "high cloud.
The ice crystals happen to be aligned tangent or horizontal with respect to the sun.
Zidle said the crystals act as prisms which bend the light from the sun and display vivid colors of the spectrum on the cloud.