Circumzenithal arc

A few of us were on a walk at Votier's Flats, Fish Creek Park, on 4 February 2013, when we noticed an area of cloud that was changing with all the colours of the rainbow. I don't think any of us had ever seen this before - it was beautiful! On Wikipedia, I read that: "The arc has a considerable angular extent and thus, rarely is complete. When only fragments of a cirrus cloud are in the appropriate sky and sun position, they may appear to shine with spectral colours." Does anyone happen to know what this exactly is?

Later: this is a reply I just received from Paul Dunphy, who is Global Calgary's weather expert on Global TV, weekdays at 5:00, 6:00 and 11:00 p.m.. He is an endorsed weathercaster of the Canadian Meteorological and Oceanographic Society, and has been delivering the forecast on Global Calgary since 1985. Thanks so much, Paul, for your help with this - difficult, I know, to tell from just one single image.

"You’re pretty close with the name, it’s a circumzenithal arc. And you’re right about it being hard to tell from one photograph. It could indeed be part of a circumzenithal arc but I can’t tell from this shot." He kindly sent me the two links below.

www.google.ca/search?q=circumzenithal+arc&hl=en&q...

en.wikipedia.org/wiki/Circumzenithal_arc