Deborah Hodgins says she felt blessed to witness this incredible sundog on Tuesday during a mid-morning trip up to Rossland for breakfast.
Wondering what causes a sundog?
A sundog, also known as a parhelion, is an atmospheric optical phenomenon that consists of bright spots appearing on either side of the sun, often forming a halo-like effect.
Sundogs are typically seen when the sun is low on the horizon and can be observed at any time of the year.
Formation
Sundogs are caused by the refraction of sunlight through ice crystals in the atmosphere, particularly in cirrus or cirrostratus clouds. The light is bent, or refracted, at an angle of about 22 degrees, creating the bright spots on either side of the sun.
Specific conditions necessary for sundogs to form include: presence of ice crystals, the atmosphere must contain ice crystals, which are usually hexagonal and plate-like; sun position, the sun needs to be low in the sky, typically within 30 degrees of the horizon; and orientation of crystals, the ice crystals must be oriented horizontally to refract the sunlight effectively.
Appearance
Sundogs are often colourful, with red appearing on the side closest to the Sun and blue or green hues on the outer edges.
This coloration is due to the dispersion of light, similar to the way a prism works.
They appear as bright spots, sometimes with a more diffuse, halo-like appearance extending outward.
Significance
Sundogs are an example of how atmospheric conditions can create beautiful and intriguing visual effects.
They are often seen as a sign of changing weather, particularly indicating the approach of a frontal system, as the cirrus clouds in which they form are typically found ahead of warm fronts.
Other Phenomena
Sundogs are part of a larger family of halos and arcs caused by the interaction of sunlight or moonlight with ice crystals in the atmosphere.
Other related phenomena include: halos, or circular rings around the sun or moon; pillars, which are vertical columns of light extending above or below a light source; and circumzenithal arcs, upside-down rainbow-like arcs located directly overhead.
