This is the breathtaking moment a "fire rainbow" — more accurately known as a circumhorizontal arc — showed up to charm the people in Kuala Lumpur, Malaysia on May 28. br br A circumhorizontal arc is an optical phenomenon that belongs to the family of ice halos formed by the refraction of sun — or moonlight in plate-shaped ice crystals suspended in the atmosphere — typically in cirrus or cirrostratus clouds.