Diversity in the sky – CIRCUMHORIZONTAL ARC is the rainbow’s flashier cousin

The sky spans over countries, across borders, and hovers over ALL of us. It’s cool when the sky shows us its diversity…sometimes its grey (somber?), sometimes its bright blue (happy?), sometimes its yellow (mellow?), sometimes its red (passionate?), sometimes its pink (coy and flirty?), sometimes its orange (brilliant!), and every night its navy (sleepy?).

And sometimes, when the sky is feeling fantastic after a cleansing shower it will produce a colourful rainbow. Or better yet a fiery rainbow called a CIRCUMHORIZONTAL ARC when the sky really wants to show off.

This one appeared on June 3rd in northern Idaho, USA, near the Washington State border. The rare arc occurs when light passes through wispy, high-altitude cirrus clouds and ice crystals (crack open that geography textbook!), and only occurs when the sun is very high in the sky. The fiery rainbow spans several 100 square miles of sky and primps and shows-off for about an hour.

More:
*Original source from Victoria Gilman @ www.nationalgeographic.com.
*For a more scientific explanation of a CIRCUMHORIZONTAL ARC, go to Atmospheric Optics (HERE).