Weather Whys: What are sun pillars?

In today's Weather Whys Meteorologist Justin Thompson-Gee explains how sun pillars form. 

Around January 19 photos from viewers around southeast Wisconsin started flooding in of light beaming straight up from a setting sun. The light is called a sun pillar. Sun pillars form when light reflects off millions of tiny ice crystals with hexagonal faces falling from high clouds like cirrus. The light reflects off the crystals into a beam of light. The pillars are most often seen on the western sky around sunset. 

A more appropriate name is "light pillar" since the phenomena can be seen from the moon, street lights or even city lights on the horizon.

Light pillars are a frequent cause for UFO sightings.