Feb 23 2014

Light Pillars

Published by at 7:30 am under Weather & Sky

Light pillars in Laramie, Wyoming (photo from Wikimedia Commons, Creative Commons license)

Last weekend on PABIRDS, Bill Drolsbaugh reported seeing light pillars at night in Sharon, PA.

He wrote:

Around 3 a.m.there were ice columns or pillars suspended above strong lights in Sharon Pa Quaker Steak and lube parking lots to the East [and]  NLMK steel plant on the horizon about a mile away to the s.w.    They are vertical refractions that can be seen in very cold temps and suspended fine snow above lights and have tall vertical rainbow-like qualities.  One of them was floating in front of my window about 20 ft out suspended in mid air like a Winter Wraith.

I’ve never seen light pillars so I looked for photos online and found this one taken in Laramie, Wyoming.

In the photo, the pillars look as if they shine straight up from each streetlight but as Les Cowley explains on his Atmospheric Optics website, they’re caused by reflections from millions of flat plate-like ice crystals between the light source and the observer.  This explains why Bill saw one floating 20 feet outside his window.

Click on Les’ diagram below to see it full size and read more about this optical phenomenon.

Diagram of light pillars by Les Cowley, Atmospheric Optics

 

As winter gives way to spring there will be fewer opportunities to witness these icy phenomena.  Given the choice I think we’d rather have warm weather than light pillars.

(photo of light pillars from Wikimedia Commons. Diagram of light pillars by Les Cowley at Atmospheric Optics.  Click on the images to see the originals.)

One response so far

One Response to “Light Pillars”

  1. bhanceyon 23 Feb 2014 at 2:14 pm

    What a beautiful photo!
    And a treat to hear mention of Sharon. I grew up there – and my uncles and I were regular customers of Quaker Steak and Lube during the first years it was open, before each of us eventually moved to other cities, or states. My grandfather donated some of the historic automobile artifacts to the original owners to hang on the walls. It was a wonderful place to stop for dinner, cook your own steak, make your own salad, and meet some nice folks.

    I have never seen such spectacular ice pillars, but have seen hints of them from time to time. Thanks for the explanation for their occurance.

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