Explanation:
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 taken late last month, a
sun-pillar reflects light from a Sun setting over
Bangor, Maine,
USA.