VirusHead

Aunt Elaine sent me this, a circulating email. I always check these out. This one is not a hoax.

The email calls this the rarest of all atmostpheric phenomena, a “fire rainbow.” Clouds have to be cirrus, at least 20k feet in the air, with just the right amount of ice crystals and the sun has to hit the clouds at precisely 50 degrees.

Yup, you get the right combination of conditions and – voila! beauty.

From Snopes

This is a real photograph of an atmospheric phenomenon known as a circumhorizon(tal) arc, the example shown above was captured on camera as it hung for about an hour across a several-hundred square mile area of sky above northern Idaho (near the Washington border) on 3 June 2006.

In general, a circumhorizontal arc (or “fire rainbow”) appears when the sun is high in the sky (i.e., higher than 58° above the horizon), and its light passes through diaphanous, high-altitude cirrus clouds made up of hexagonal plate crystals. Sunlight entering the crystals’ vertical side faces and leaving through their bottom faces is refracted (as through a prism) and separated into an array of visible colors. When the plate crystals in cirrus clouds are aligned optimally (i.e., with their faces parallel to the ground), the resulting display is a brilliant spectrum of colors reminiscent of a rainbow.

Well, I think it’s more than “reminiscent” of a rainbow. It’s the normal prism effect – but angled out over flame-shaped clouds.

Gorgeous, isn’t it?