A Fire Rainbow over West Virginia

• A rare atmospheric phenomenon known as a "fire rainbow" (circumhorizontal arc) was captured in a 2021 photograph near North Fork Mountain, West Virginia.
• The effect is created by sunlight refracting through ice crystals within high-altitude cirrus clouds.

Scientific Requirements for Formation

• Solar position: The Sun must be at an elevation of at least 58 degrees above the horizon.
• Cloud composition: Cirrus fibratus clouds must be present, containing flat, hexagonal ice crystals.
• Crystal alignment: The crystals must be aligned horizontally to act effectively as prisms, refracting the sunlight in a uniform manner.

Phenomenon Characteristics

• Appearance: It is named for its flame-like, vibrant appearance and creates an arc that runs parallel to the horizon.
• Rarity: Because specific solar angles and cloud alignments must coincide, circumhorizontal arcs are considered an unusual sight.