Light pillars in North Bay, Ontario. Light pillars appear when either natural or artificial light bounces off ice crystals floating close to the ground. In this case, the air was so cold that ice crystals were forming in the air, reflecting the city’s street and business lights.
Photo credit: Timothy Joseph Elzinga
Out here, we will occasionally get a light pillar from very high altitude clouds, which are really ice crystals. As the sun goes down, it's light shines up through the crystals, generating one big column.