Strange Colorful Clouds

July 22, 2005 at 1:01 am | Posted in Uncategorized | Leave a comment

If you were outside in Fort Worth early Thursday afternoon, you may have witnessed a very strange phenomenon in the sky overhead. Some of the clouds became a shimmering, irridescent, and very colorful display.

If, like me, you missed it, you have a second chance. We have 10 images of the cloud from different viewers in a slideshow, at: http://www.nbc5i.com/weather/4753431/detail.html

Upon seeing the photos, my first thought was that it was related to some type of parhelia, or sun dog. These are phenomena that occur as the result of sunlight being refracted by the ice crystals in cirrus clouds. In fact it looks somewhat like photos of something called a circumzenithal arc. Check out the following links:
http://www.sundog.clara.co.uk/halo/cza.htm
http://www.sundog.clara.co.uk/halo/czaim1.htm
But a circumzenithal arc only occurs when the sun is at 32 degrees or less above the horizon. And at midday on a July afternoon in Texas, the sun is much higher than that. So that possibility seems to be ruled out.

One viewer suggested that the colors may have been due to a “fuel dump” from an aircraft. The possible spray of aircraft fuel might indeed have contributed to the prismatic effect, much like oil droplets glistens on a water surface. But we have no data to back up that hypthesis. So for now the details remain a mystery, although it almost certainly was some kind of optical effect of sunlight refracting through cloud ice crystals.

Here are a number of other links with more general information, and some spectacular photos of some of the other various types of parhelia and other atmospheric optical phenomena:
http://www.sundog.clara.co.uk/atoptics/phenom.htm
http://en.wikipedia.org/wiki/Sun_pillar
http://www.w7ftt.net/sundog1.html
http://asuaf.org/~johnc/SunHalos.html
http://www.photoastronomique.net/photo_us.php?nom=0408100082

Advertisements

Leave a Comment »

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Create a free website or blog at WordPress.com.
Entries and comments feeds.

%d bloggers like this: