A rare phenomenon was seen in Arkansas on Monday morning with the dense fog. It goes by many names, like white rainbow, ghost rainbow, mistbow, Bouguer’s Halo, or sea-dog, but many know it as a fogbow.
A fogbow forms similarly to a rainbow, with tiny water droplets and sunlight. Same as a rainbow, a fogbow appears on the opposite side from the sun, forming due to the scattering of sunlight through tiny water droplets. In a rainbow, the sunlight scatters through raindrops. In a fogbow, the sunlight scatters through the tiny water droplets that make up fog.
Because the droplets that make up fog are much tinier than raindrops, they don’t scatter the sunlight as well. That means instead of a colorful bow, it’s a ghostly white bow. Also, due to the size of fog droplets, fogbows are often bigger and broader than a rainbow. Sometimes, fogbows can have a narrow band of red or blue at the edges, though.
They’re a rare sight, and mostly occur when the sun is at a low angle in the sky. This means a morning or evening sun is optimal for a fogbow to occur.
Other spots to see fogbows, besides a moment with a low-angled sun and fog, include at sea or at high altitudes (like on a mountain or from an airplane)…