This high, very thin layer of small, uniform, tiny cloudlets was observed in Boulder, Colorado on March 23, 2011. Since each of the cloudlets is less than a degree wide and unshaded, the cloud formation fits the World Meteorological Organization definition of cirrocumulus. However, there is some evidence that the cloud is altocumulus rather than cirrocumulus. For a discussion, see UCAR Magazine's Currents article at http://www2.ucar.edu/currents/cloud-remember-and-mystery-solve.