A rare white rainbow, also known as a "fogbow," has been photographed in Puntagorda, La Palma, by local resident Tomás Martín.
This unusual meteorological phenomenon occurs under specific conditions involving significant fog in the atmosphere, unlike the more familiar coloured rainbow, which requires rainfall to form.
Unlike a colourful rainbow that forms when sunlight interacts with larger raindrops, a white rainbow occurs when sunlight is refracted, reflected, and diffracted by tiny water droplets found in fog or mist.
How It Forms:
1. Droplet Size: Fog droplets are much smaller than raindrops, usually less than 0.05 millimetres in diameter.
2. Light Scattering: These small droplets scatter light more diffusely, which prevents the clear separation of colours. This results in a pale, almost white arc instead of the vivid bands of a rainbow.
3. Location: A fogbow is typically seen when the observer is standing with the sun behind them, looking into a bank of fog.
Appearance:
Where You Might See It:
Fogbows are most often observed:
Fogbows require very specific conditions, including the right size of water droplets, the presence of fog, and proper sunlight angles, which makes them far less common than regular rainbows.
