The Weather Notebook: Listener Question: A Flashlight Sunrise

Listener Question: A Flashlight Sunrise
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It's listener question day once again here on The Weather Notebook. I'm Dave Thurlow. Today we hear from an astute observer about a rather rare optical phenomena.

View SSW from Asheville, North Carolina December 26, 1978. Photographer: Grant W. Goodge NOAA Photo Collection
"Good morning Dave. This is Tom Brown calling from Buffalo, NY area. I listen to NPR and The Weather Notebook via WBFO. I have a weather question. From the horizon this morning, [during] the sunrise, part of the light scattered by the sun seemed to project in an intensified area as a flashlight beam shining up vertically, perfectly vertically. And it's quite noticeable from a normal sunrise and wondered what might cause this. The only thing I happened to notice, it seems to happen on very cold mornings, clear mornings, the sky's basically cloudless. Thank you."

Well, that's a pretty good description, which makes it easy to pinpoint what you saw as a sun pillar. Sun pillars result from sunlight reflecting off ice crystals suspended in the air. These ice crystals can be up about 5 miles high in what are called cirrus clouds, or they can be close to the ground. You can see sun pillars when the sun is below the horizon from your perspective, but its light still reaches ice crystals in the air above the horizon. The light simply is reflected off the flat bottom surface of the flat or column shaped crystals, and only the crystals that are in line with you and the sun direct the sparkling light to your eyes. Therefore, it looks like a pillar of light. Pillars can also form from moonlight or from artificial light creating some mysterious nighttime effects.

For illustrations and pictures of pillars, check out www.mountwashington.org. The Weather Notebook is a production of the Mount Washington Observatory.