A Sun Pillar.

Have you ever seen a sun pillar ? When the air is cold and the Sun is rising or setting , falling ice crystals can reflect sunlight and create an unusual column of light. Ice sometimes forms flat, stop-sign shaped crystals as it falls from high-level clouds . Air resistance causes these crystals to lie nearly flat much of the time as they flutter to the ground. Sunlight reflects off crystals that are properly aligned, creating the sun-pillar effect. In the above picture , a sun-pillar reflects light from a setting Sun.