NASA has highlighted an image of a fire rainbow, or circumhorizontal arc, captured over West Virginia. This atmospheric optical phenomenon occurs when sunlight passes through flat, hexagonal ice crystals in cirrus clouds, refracting in a manner similar to a prism. For it to be visible, the Sun must be at an altitude of at least 58 degrees above the horizon, which limits its appearance to certain times of day and seasons, and the orientation of the ice crystals must be horizontal and parallel to the ground.

The circumhorizontal arc is distinguished by its horizontal rainbow-like appearance and intense coloration, often described as flame-like, hence its popular name. Although commonly associated with the term "fire rainbow," it has no relation to fire. Its formation depends on a precise combination of atmospheric conditions: the presence of cirrus clouds composed of ice crystals, a high solar position, and the specific alignment of these crystals. Such phenomena serve as a reminder of the complex interaction between sunlight and the Earth's atmosphere.