Earlier this month, I observed a sunset that I couldn’t quite explain. While an occasional solar halo or a pair of sun dogs are known to entertain us pilots at higher altitudes, this wasn’t one of those. This sunset was accompanied by two perfectly vertical rainbow-colored columns of light.
The best photo I took was the right side of the sunset with one of the vertical features.
I tried to find any other example of this phenomenon and didn’t find a good one with a technical description. A rainbow or a halo would be obviously round. A sun dog would be parallel to the horizon instead of vertical. A sun pillar would be above the sun instead of on the sides.
For a guess, this vertical rainbow phenomenon might be a partial halo at the top end with a reflected image below, creating an illusion of a vertical beam.