Tuesday, February 15, 2022

Ice Pillars - The Light Sabers of the Sky

The atmosphere is an amazing creation, and some of the things that go on up there are truly “out of this world”. One that I have been treated to only rarely is something right out of Star Wars. Everyone must be familiar with the light sabers that were part of Jedi Order, and that’s what I am reminded of when I see Ice Pillars in the sky. Click on the video below to get a better idea of how they look in real life. 

Ice pillars, also known as Light Pillars are another one of the amazing optical phenomena that occur in our atmosphere.  The are formed under very special conditions and therefore are quite rare. There are a few ingredients necessary for the formation of Ice Pillars.  You need very cold air temperatures, usually below 15°F, which allows for the formation of ice crystals, hexagonal plates or dendrites that are necessary for the reflection of light rays from the source. Those kinds of temperatures immediately eliminate most of the populated regions of the globe so that it’s a feature normally seen at the higher latitudes of both hemispheres on earth.  Those ice crystals, either fall gently down to the ground or float in the air as you would see in ice fog. In addition, because the crystals need to take on a certain flat configuration in the air and not be jostled about so they can reflect light rays properly, the air needs to be almost still. 

Now once you have all of these conditions in place, how in the world do the pillars of light form? That is where the optics of the atmosphere comes in. Light rays that come off a point source, most commonly street lights, are normally directed up into the sky in all directions. All ice crystals present in the atmosphere reflect the light from the source. But only those crystals that are aligned in a common vertical plane will direct the light towards the observer. If a person is lucky enough and is at the right angle looking back toward the light source, their eyes will see light rays that have been reflected off a column of those perfectly aligned ice crystals. The result is that the eye perceives a column of light above the light source. It is not a real column of light, rather an illusion created by the ice crystals reflecting that light. 

Different colored light sources will result in different colored columns in the air. I have seen red light pillars that came off runway lights at an airport as well as train yards. The pillars I saw in these photos came off sodium lamps and they have that eerie, soft yellow glow to them.  

Winter is an amazing season. So much of what we experience outdoors can seem other-worldly at times. From beautiful snowflakes to ice needles and rime ice, ribbon ice, ice pillars to the blanket of white that covers the ground, allows for us to ski, skate on frozen water, it truly is a magical season. Keep your eyes open and you can find some of these hidden gems if you take the time to look and explore. Enjoy!!