A Fire Rainbow

A medium told me Shayna takes great pride in sending rainbows to me. This is a special one. It had not rained at all day. I looked up as we were finishing our round of golf and saw this.

As with most things miraculous, there is a current scientific explanation for the phenomenon. In this case, it is a rare seldom seen rainbow that occurs when conditions are just right. Wikipedia gives it the name “Circumhorizontal Arc:”

“A circumhorizontal arc or circumhorizon arc (CHA), also known as a fire rainbow, is a halo or an optical phenomenon similar in appearance to a horizontal rainbow, but in contrast caused by the refraction of light through the ice crystals in cirrus clouds.
It occurs only when the sun is high in the sky, at least 58° above the horizon, and can only occur in the presences of cirrus clouds. It can thus not be observed at locations north of 55°N, except occasionally from mountains.

The phenomenon is quite rare because the ice crystals must be aligned horizontally to reflect the high sun. The arc is formed as light rays enter the horizontally-oriented flat hexagonal crystals through a vertical side face and exit through the horizontal bottom face. It is the 90° inclination that produces the well-separated rainbow-like colours and, if the crystal alignment is just right, make the entire cirrus cloud shine like a flaming rainbow.

Another reference notes: “The arc is a very large halo and is close to, and parallel to the horizon. Usually only fragments are visible where there happen to be cirrus clouds.” In other words a rainbow so big that it rolls right on out of the sky.
Still another sighting via National Geographic News adds:

“The arc isn’t a rainbow in the traditional sense – it is caused by light passing through wispy, high-altitude cirrus clouds. The sight occurs only when the sun is very high in the sky (more than 58° above the horizon). What’s more, the hexagonal ice crystals that make up cirrus clouds must be shaped like thick plates with their faces parallel to the ground.”

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