An Exceptionally Rare Phenomenon Was Captured in  Photos. A Horizontal Rainbow Filled the Sky!

Horizontal rainbows are very rare. This one was seen a couple of weeks ago near Lake Sammamish, King county, Washington state, US. The photo was taken by Cessna Kutz.

This kind of rainbow is also referred to as fire rainbow or circumhorizontal arc. It does not occur everywhere. To see a rainbow like this, certain conditions have to be met. The Sun has to be higher than 58 degrees over the horizon and at the same time high-altitude cirrus clouds have to be present.

Theoretically it is not a rainbow, as this phenomenon has got nothing to do with rain. It occurs thanks to haze-containing plate-shaped ice. It forms a kind of dust in the clouds and the Sun, shining through them creates the phenomenon in question.

The phenomenon is more common near the equator. However, it might be occasionally seen in northern locations. One was seen in Puck, Poland in 2015.