Circumzenithal Arc and Extreme Virga

This extraordinary group of clouds moved in rapidly from the west. There are several pathes of cloud each trailing very long wisps of virga.

As one of the patches passed over a few minutes later a circumzenithal arc was visible.

From the way the right edge of the arc is cut off it is clear that it was formed by crystals in the falling virga not the parent cloud above.

Canon EOS 20D   10th October 2009
Wiltshire, England

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