A fire rainbow, one of the rarest atmospheric phenomena, was spotted on the Idaho and Washington border and lasted about an hour. For a fire rainbow to form, cirrus clouds need to be at least 20,000 feet high with the perfect amount of ice crystals, and the sun has to hit the clouds at an exact 58 degree angle.

1. Fire Rainbow A fire rainbow is one of the rarest naturally occurring atmospheric phenomena. The picture was captured on the Idaho & Washington border. T he event lasted about 1 hour. Clouds have to be cirrus, at least 20,000 feet in the air, with just the right amount of ice crystals and the sun has to hit the clouds at precisely 58 degrees.